Accounting Foundations

Accounting is the symbolic language of economic activity. It translates the messy reality of contracts, inventories, customer promises, employee compensation, and asset wear-and-tear into a finite ledger that lenders, equity holders, regulators, and tax authorities can compare across companies, industries, and decades. Two principal frameworks — US GAAP (Generally Accepted Accounting Principles) and IFRS (International Financial Reporting Standards) — govern most of the world’s public reporting; the rest of this note unpacks how they work, what the statements show, how analysts interrogate them, and how the system has been broken (and patched) over the past three decades.

Companion notes: corporate-finance-and-markets, investments-and-portfolio-management, derivatives-and-quant-finance, microeconomics, securities-and-corporate-law.

1. The two frameworks: GAAP vs IFRS

1.1 Standard-setters

FASB (Financial Accounting Standards Board, Norwalk CT, founded 1973). Issues Accounting Standards Codification (ASC) — the comprehensive, topic-numbered restatement of US GAAP since 2009. Funded by accounting-support fees on public companies under SOX §109. Currently chaired by Richard Jones.
IASB (International Accounting Standards Board, London, founded 2001 from the IASC). Issues IFRS Standards (IFRS 1, IFRS 2, …) and inherited IAS pronouncements (IAS 1, IAS 2, …) from its predecessor. Chair: Andreas Barckow.
SEC (Securities and Exchange Commission): requires US GAAP for domestic registrants; foreign private issuers may file in IFRS without reconciliation.
PCAOB (Public Company Accounting Oversight Board): created by Sarbanes-Oxley 2002; oversees auditors of US public companies. Inspects Big Four annually, smaller firms triennially.

1.2 Coverage

US GAAP: required for SEC registrants; also dominant among US private companies (often via “FRF for SMEs” or modified GAAP). ~10,000 public filers + millions of private.
IFRS: required or permitted in 140+ jurisdictions including EU (since 2005), UK, Canada (since 2011 for public), Australia, Brazil, S. Korea, Saudi Arabia, India (Ind AS converged). Japan permits optional adoption; China has converged Chinese Accounting Standards (CAS) substantially.

1.3 Convergence and divergence

The FASB-IASB Norwalk Agreement (2002) and Memorandum of Understanding (2006) drove ~15 years of convergence work. Major successes:

Revenue recognition: ASC 606 + IFRS 15 are essentially identical (effective 2018).
Leases: ASC 842 + IFRS 16 both bring operating leases on balance sheet (effective 2019), but classification rules differ (IFRS 16 single-model lessee accounting; ASC 842 retains operating vs finance distinction for P&L pattern).
Financial instruments: ASC 326 (CECL, current expected credit loss) for US banks; IFRS 9 expected-credit-loss model for the rest.

Active divergences remaining: inventory (LIFO permitted under GAAP, banned under IFRS); R&D (GAAP expenses, IFRS capitalizes development phase); impairment (GAAP 2-step for long-lived assets, IFRS single step); inventory write-down reversals (allowed under IFRS, banned under GAAP); revaluation model for PP&E and intangibles (IFRS allows, GAAP doesn’t).

Formal convergence efforts paused around 2014; both boards now coordinate but pursue independent agendas.

2. Conceptual framework

Both FASB Concepts Statements (notably CON 8) and the IASB Conceptual Framework articulate the qualitative characteristics underlying useful financial information.

2.1 Fundamental qualitative characteristics

Relevance: predictive value, confirmatory value, materiality.
Faithful representation: complete, neutral, free from error.

2.2 Enhancing qualitative characteristics

Comparability (across firms and across time).
Verifiability (different observers reach consensus on representation).
Timeliness (information arrives in time to influence decisions).
Understandability (clear and concise for users with reasonable knowledge of business).

2.3 Elements

Assets: probable future economic benefits controlled by the entity from past transactions.
Liabilities: probable future sacrifices of economic benefits arising from present obligations.
Equity: residual interest in assets after deducting liabilities (Assets − Liabilities).
Revenues: inflows from delivering goods/services in ongoing operations.
Expenses: outflows incurred to generate revenue.
Gains / losses: from peripheral or incidental activities (sale of a building, settlement of litigation).

Recognition + measurement = when an element enters the books and at what amount (historical cost, fair value, amortized cost, net realizable value, present value).

3. The basic equation and double-entry bookkeeping

3.1 The accounting identity

Assets = Liabilities + Equity

Every transaction must keep this balanced. Equity expands via net income and capital contributions; contracts via losses and distributions.

3.2 Double-entry origins

Luca Pacioli (1494), in Summa de Arithmetica, published the first systematic Western treatment of double-entry bookkeeping as practiced by Venetian merchants. Every debit has an equal and opposite credit.

Debit increases: assets, expenses, losses.
Credit increases: liabilities, equity, revenues, gains.
The mnemonic DEALER: Dividends/Drawings + Expenses + Assets on the debit side; Liabilities + Equity + Revenues on the credit side.

A T-account is the analytical primitive. The general ledger (GL) is the aggregate of all accounts; trial balance is a periodic check that debits = credits.

4. Cash vs accrual accounting

4.1 Cash basis

Revenue when cash received; expense when cash paid. Permitted for very small US businesses (under $30M average gross receipts post-TCJA §448 indexation) and most individuals. Distorts performance whenever timing of cash and economic activity diverge — i.e. almost always at scale.

4.2 Accrual basis

GAAP and IFRS require accrual accounting for most entities. Revenue is recognized when earned; expenses when incurred, regardless of cash timing.

The matching principle: match expenses to the revenues they help generate in the same period. Drives concepts of cost of goods sold (matched to revenue), depreciation (capex matched over useful life), and accruals (accrued payroll, accrued interest).

4.3 ASC 606 / IFRS 15 — revenue recognition (effective 2018)

The most important convergence project. Five-step model:

Identify the contract with a customer (approved, identifiable rights, payment terms, commercial substance, collectibility probable).
Identify the performance obligations (distinct goods/services).
Determine the transaction price (including variable consideration estimates — expected value or most likely amount — constrained to amounts highly probable of not reversing).
Allocate transaction price to performance obligations based on relative standalone selling prices.
Recognize revenue when (or as) each performance obligation is satisfied (point in time vs over time).

Industry applications:

SaaS subscription: recognize ratably over contract term (over time).
Perpetual license + maintenance: bifurcate; license recognized at delivery, maintenance ratable.
Long-term construction: % of completion based on cost-to-cost or output measures (preserved from prior ASC 605-35 / IAS 11).
Milestone-based (pharma R&D collaborations): recognize when milestone probable and consideration reliably estimable.
Bill-and-hold: revenue at point of “sale” only if customer requested, goods are identified separately, ready for transfer, and seller cannot use them.

Capitalize costs to obtain a contract (sales commissions on multi-year contracts) and amortize over expected customer life. ASC 340-40 / IFRS 15 §91-94.

5. The financial statements

5.1 Statement of Financial Position (Balance Sheet)

A snapshot at a point in time. Assets = Liabilities + Equity.

US GAAP convention: classified balance sheet, current first then non-current; current/non-current threshold is the longer of 12 months or operating cycle.

Section	Examples
Current assets	Cash & equivalents, marketable securities, accounts receivable (net of allowance), inventory, prepaid expenses, contract assets
Non-current assets	PP&E (net of accumulated depreciation), right-of-use lease assets, intangibles (definite-life — patents, customer relationships), goodwill, long-term investments, deferred tax assets
Current liabilities	Accounts payable, accrued expenses, deferred revenue/contract liabilities, short-term debt, current portion of long-term debt, current lease liabilities, income tax payable
Non-current liabilities	Long-term debt, long-term lease liabilities, deferred tax liabilities, pension obligation, operating-segment provisions
Equity	Common stock (par), additional paid-in capital (APIC), retained earnings, treasury stock (contra), accumulated other comprehensive income (AOCI), non-controlling interest

5.2 Income Statement (Statement of Operations / Profit or Loss)

A flow over a period. Revenue − Expenses = Net Income.

Standard hierarchy:

Revenue
  − Cost of revenue / COGS
= Gross profit
  − Selling, general & administrative (SG&A)
  − Research & development (R&D)
  − Depreciation & amortization (if not in COGS or separate)
  − Restructuring / impairment charges
= Operating income (EBIT)
  + Other income / (expense), net
  − Interest expense, net of interest income
= Pre-tax income
  − Income tax expense
= Net income
  / weighted average shares = Basic EPS
  / diluted weighted shares = Diluted EPS

Comprehensive Income = Net income + Other Comprehensive Income (OCI). OCI items: foreign-currency translation, unrealized gains/losses on AFS debt securities (US GAAP), pension remeasurements (IFRS), effective portion of cash-flow hedges.

5.3 Statement of Cash Flows

Reconciles opening cash to closing cash through three buckets:

Operating: cash from core business operations.
- Indirect method (overwhelmingly common): start with net income, add back non-cash items (D&A, stock-based comp, deferred tax, impairment, gains/losses on sale), adjust for changes in working capital (ΔAR, Δinventory, ΔAP, Δdeferred revenue).
- Direct method (rare in practice; IFRS encourages): cash receipts from customers minus cash paid to suppliers/employees.
Investing: capex, acquisitions, divestitures, purchases/sales of marketable securities, capitalized software development.
Financing: debt issuance/repayment, equity issuance/repurchase, dividends paid, lease principal payments.

US GAAP allows interest paid in operating, while IFRS allows interest paid in operating or financing (and dividends paid in operating or financing) — a real cross-border comparability gotcha.

5.4 Statement of Changes in Equity

Roll-forward by component: common stock + APIC, retained earnings, treasury stock, AOCI, non-controlling interest. Shows transactions with owners (issuances, repurchases, dividends) distinctly from comprehensive income.

5.5 SEC filings

10-K: annual report; audited financials; MD&A; risk factors; controls assertion. Due within 60 days (large accelerated), 75 (accelerated), 90 (non-accelerated) of fiscal year end.
10-Q: quarterly; reviewed (not audited) by external auditor.
8-K: material event disclosure (M&A, CEO change, going-concern auditor opinion, bankruptcy, ratings change, departures, exhibit additions). Due within 4 business days.
20-F: foreign private issuer annual.
Proxy DEF 14A: executive compensation, director elections, shareholder proposals.

6. Balance sheet items in depth

6.1 Cash and equivalents

Cash + short-term investments ≤ 3 months original maturity with insignificant interest-rate risk (T-bills, commercial paper, MMFs). Restricted cash disclosed separately.

6.2 Accounts receivable

Carried at amortized cost net of allowance for expected credit losses (ASC 326 CECL, IFRS 9 ECL). CECL effective 2020 for SEC filers, big-bang change from incurred-loss model — banks took massive day-one allowances. Aging analysis underpins reserve estimates.

6.3 Inventory

Held at the lower of cost and net realizable value (NRV = selling price − costs to complete and sell). Cost flow assumptions:

FIFO (First In, First Out): oldest cost layers flow to COGS first. Balance sheet inventory at recent costs.
LIFO (Last In, First Out): newest cost layers to COGS. Reduces taxable income in inflation. Allowed under US GAAP, banned under IFRS. LIFO reserve disclosed = FIFO − LIFO inventory. LIFO conformity rule (US tax): if you use LIFO for tax, you must use it for book.
Weighted-average (perpetual or periodic).
Specific identification (used for large unique items — cars, real estate, jewelry).
Retail method, standard cost (manufacturing).

6.4 PP&E (Property, Plant & Equipment)

Capitalize if it provides future economic benefit beyond one year and meets a threshold (typically $1 k -$ 10k per asset depending on company policy). Expense routine repairs and maintenance.

Depreciation methods:

Straight-line: (Cost − Salvage) / Useful life. Most common.
Declining balance (e.g. double-declining, 200% DDB): accelerated; (2/n) × NBV.
Sum-of-the-years’-digits: another accelerated method.
Units of production: depreciation per unit × actual units. Mining, transportation fleets.
MACRS (tax-only, US): IRC §168 prescribed lives and methods; 5/7/15/27.5/39-year classes. Bonus depreciation under §168(k): 100% (2017–2022), 80% (2023), 60% (2024), 40% (2025), 20% (2026), 0% thereafter unless legislatively extended.

Impairment:

US GAAP (ASC 360 — long-lived assets held for use): 2-step. (1) Recoverability test — sum of undiscounted future cash flows < carrying value triggers impairment. (2) Measurement — impairment loss = carrying value − fair value (discounted).
IFRS (IAS 36): single step. Carrying value vs recoverable amount = max(FV − costs to sell, value in use = PV of future cash flows).
IFRS permits impairment reversal (other than goodwill); GAAP does not.

6.5 Intangible assets

Definite-lived intangibles: patents, copyrights, customer relationships, developed technology, non-compete agreements. Amortize over useful life (straight-line typical).
Indefinite-lived intangibles: trademarks/trade names without foreseeable termination. Not amortized; tested for impairment annually (or more often on triggering events).
Goodwill: residual of purchase price over identifiable net assets at acquisition. Not amortized under either framework since 2001 (US) / 2004 (IFRS) — annual impairment test required (ASC 350 / IAS 36).
- GAAP impairment test (simplified by ASU 2017-04): one-step — carrying value of reporting unit vs fair value; loss capped at goodwill carrying amount.
- Private companies (US): can elect ASU 2014-02 alternative — amortize goodwill straight-line over 10 years (or less).
R&D treatment — major GAAP/IFRS divergence:
- GAAP (ASC 730): Expense as incurred. Internal-use software development costs (ASC 350-40) and capitalizable software developed for sale (ASC 985-20) are narrow exceptions.
- IFRS (IAS 38): Expense research phase; capitalize development phase if six criteria met (technical feasibility, intent to complete, ability to use/sell, future benefits demonstrated, resources available, expenditures reliably measured).

6.6 Investments in financial instruments

US GAAP (ASC 320, 321, 825) and IFRS 9 classify based on business model + cash-flow characteristics:

Category	GAAP	IFRS 9
Held for collection of contractual cash flows	Amortized cost	Amortized cost
Held for collection AND sale	AFS (FV through OCI)	FVOCI with recycling
Held for sale	Trading (FV through P&L)	FVPL
Equity securities	FV through P&L (ASC 321 since 2018)	FVPL or FVOCI (no recycling — irrevocable election)
Equity method (significant influence, 20–50%)	Same	Same (IAS 28)

6.7 Liabilities

Accounts payable: invoiced unpaid amounts.
Accrued expenses: incurred but not yet invoiced (payroll, utilities, interest, taxes).
Deferred revenue / contract liabilities: cash received before performance obligation satisfied (SaaS prepayments, retainer fees).
Debt: bank loans, bonds, notes payable. Carried at amortized cost unless FV option elected. Premium/discount amortized via effective interest method.
Lease liability: present value of lease payments (see §6.8).
Asset retirement obligations (ARO, ASC 410-20): PV of legal obligation to retire long-lived assets (oil-well plugging, decommissioning).
Pension and OPEB liability: see §10.
Deferred tax liability: see §8.
Contingent liabilities (ASC 450 / IAS 37): accrued if probable + reasonably estimable (GAAP) or more likely than not + reliably estimable (IFRS). Disclosed if reasonably possible / not remote.

6.8 Lease accounting (ASC 842 / IFRS 16, effective 2019)

Both frameworks bring operating leases onto the balance sheet for lessees.

Right-of-use (ROU) asset: lease liability + prepayments + initial direct costs − incentives.
Lease liability: PV of lease payments at rate implicit in lease (or IBR — incremental borrowing rate — if implicit rate not determinable).

P&L treatment:

IFRS 16: single model — all leases produce front-loaded expense (depreciation of ROU + interest on liability — interest decreases over time).
ASC 842: retains lessee classification — operating lease produces straight-line expense (single lease cost = principal-equivalent + interest combined); finance lease produces front-loaded expense (depreciation + interest separately, like IFRS 16).

Short-term (≤12 mo) and low-value leases (~<$5k, IFRS) can be expensed off-balance-sheet.

6.9 Equity

Common stock at par + APIC (premium over par).
Retained earnings: cumulative NI − cumulative dividends − stock-based comp expense if charged to RE − other adjustments.
Treasury stock: shares repurchased and held (not retired) — contra-equity at cost (US GAAP) or par-value method.
AOCI: cumulative OCI items (FX translation, AFS unrealized G/L, pension remeasurements, cash-flow hedge reserve).
Non-controlling interest (NCI): minority share of consolidated subsidiaries’ equity.

7. Consolidation, M&A, and equity method

7.1 Consolidation thresholds

Control (>50% voting interest typically): consolidate; ASC 810 / IFRS 10. Sub’s assets, liabilities, revenues, expenses fully consolidated; NCI presented.
VIE (Variable Interest Entity, ASC 810-10): consolidate based on primary beneficiary analysis even without majority voting — exposure to expected losses + power to direct activities. Enron’s SPEs would have been VIEs under modern rules.
Significant influence (20–50%): equity method (ASC 323 / IAS 28). One-line consolidation: investment = cost + proportionate share of investee earnings − dividends; income statement reflects share of investee net income.
No significant influence (<20%): fair value through P&L (or AFS under prior GAAP).

7.2 Business combinations (ASC 805 / IFRS 3)

Pooling of interests abolished in 2001 under SFAS 141 (now ASC 805) / IFRS 3 — all acquisitions use acquisition method.

Steps:

Identify the acquirer.
Determine acquisition date.
Recognize and measure identifiable assets, liabilities, NCI at fair value.
Recognize goodwill (or bargain purchase gain).

Goodwill = consideration transferred + NCI fair value + acquirer’s previously held interest’s FV − net of identifiable assets acquired and liabilities assumed at FV.

Bargain purchase (negative goodwill): consideration < net identifiable assets at FV. Reassess valuations; if confirmed, recognize gain immediately in P&L (P&L impact, not equity).

Measurement period adjustments: up to 12 months post-close to refine provisional fair values.

Contingent consideration (earnouts): recognize at FV at close; subsequent re-measurement to FV through P&L if liability; equity-classified earnouts not remeasured.

8. Income tax accounting (ASC 740 / IAS 12)

8.1 Current vs deferred

Current tax expense: taxes payable for the period based on taxable income.
Deferred tax: arises from temporary differences between book carrying value and tax basis of assets and liabilities. Deferred Tax Liability (DTL) when book > tax basis for assets (or vice versa for liabilities); Deferred Tax Asset (DTA) vice versa.

Examples of temporary differences:

Item	Direction
Depreciation: tax MACRS faster than book SL	DTL
Stock-based comp: tax deduction on vesting/exercise > book	DTA
Deferred revenue: revenue taxed now, recognized later	DTA
Warranty accrual: book accrual, tax deduction on cash paid	DTA
Pension underfunded liability	DTA
Goodwill (taxable acquisitions, §197): 15-year tax amortization, no book amortization	DTL
Inventory reserves	DTA

Permanent differences (not deferred): tax-exempt interest (munis), §250 GILTI/FDII deductions, life insurance proceeds on key-man policies, fines and penalties.

8.2 Valuation allowance

DTAs reduced by valuation allowance if “more likely than not” (>50%) that some or all will not be realized. Heavy negative evidence: cumulative book losses, history of NOL expirations, expected continued losses. Reversal of allowance can produce massive one-time benefit (Tesla 2023: $5.0B; Twitter 2018; many cyclical recoveries).

8.3 Uncertain tax positions (FIN 48, now ASC 740-10)

Two-step: (1) recognize benefit if more-likely-than-not to sustain on technical merits; (2) measure at largest cumulative benefit with >50% probability. Reserve = expected outcome shortfall. Disclosed as UTB (Unrecognized Tax Benefit) roll-forward.

8.4 Effective tax rate (ETR)

ETR = Income tax expense / Pre-tax income. Reconciled to statutory rate in the tax footnote — most-watched footnote among analysts. Common reconciliation items: state taxes net of federal benefit, foreign rate differential, R&D credits, stock-comp windfall benefits, GILTI/FDII, BEAT, valuation allowance moves, return-to-provision true-ups.

8.5 Pillar Two (OECD global minimum tax, effective 2024)

15% effective rate at jurisdictional level for MNEs with €750M+ revenue. Income Inclusion Rule (IIR) at parent; Undertaxed Profits Rule (UTPR) as backstop; Qualified Domestic Minimum Top-up Tax (QDMTT) for source country to capture top-up before parent country claims it. Adopted by EU (Directive 2022/2523), UK, Japan, S. Korea, Canada, Australia, others. US has not adopted but is exposed via UTPR application by other countries (effective 2025+).

9. Stock-based compensation (ASC 718 / IFRS 2)

Recognize at grant-date fair value over the requisite service period (vesting).

Options: valued via Black-Scholes-Merton or lattice model (input: stock price, strike, volatility, expected term, risk-free rate, dividend yield).
RSUs (Restricted Stock Units): valued at grant-date market price; expensed straight-line over vest, less forfeitures.
PSUs (Performance Share Units): market conditions (TSR) baked into grant-date FV (no true-up); non-market performance conditions probability-weighted with true-up if outcome differs.

Tax treatment: deductible at exercise/vesting at intrinsic value (US §83). Windfall benefits/shortfalls flow to P&L (ASU 2016-09 simplified) rather than APIC.

EPS impact: see §11.

10. Pensions and OPEB (ASC 715 / IAS 19R)

10.1 Defined benefit (DB) plans

Employer promises a future benefit (e.g. final-pay × years of service × multiplier). Employer bears investment + longevity risk.

P&L components:

Service cost: PV of benefits earned in current period.
Interest cost: discount rate × beginning PBO/DBO.
Expected return on plan assets: long-term assumed return × FV of plan assets (US GAAP); under IFRS uses discount rate (more conservative).
Amortization of prior service cost and actuarial gains/losses (US GAAP only; IFRS recognizes immediately in OCI).
Settlements / curtailments when material lump-sum payouts or plan amendments.

Balance sheet: PBO − fair value of plan assets = net pension liability/asset.

US GAAP (ASC 715) allows the corridor approach or immediate recognition of OCI G/L; pushes only service cost to operating P&L line, other components below the line (ASU 2017-07).

IFRS (IAS 19R) — revised 2011 — eliminates corridor; remeasurements (actuarial G/L + return differential) recognized immediately in OCI, never recycled to P&L.

10.2 Defined contribution (DC) plans

Employer contribution defined; participant bears investment risk. Simpler accounting — expense as contributed. 401(k) is the canonical example.

10.3 OPEB (Other Post-Employment Benefits)

Retiree health care, life insurance. Similar accrual approach but historically unfunded — major liabilities for legacy auto/steel companies (GM, Ford, US Steel) pre-2007 OPEB-trust restructurings.

11.1 Basic EPS

Basic EPS = (Net income − preferred dividends − preferred deemed dividend on extinguishment) / weighted average common shares outstanding (WASO).

WASO weights share-count changes by their portion of the period.

11.2 Diluted EPS

Diluted EPS includes the effect of all dilutive potential common shares.

Methods:

Treasury stock method (options, warrants, RSUs): assume exercise/vesting; assume proceeds used to repurchase shares at average market price; incremental shares included if dilutive.
If-converted method (convertible debt, convertible preferred): assume conversion at the start of the period; add back after-tax interest / preferred dividends to numerator; add converted shares to denominator. Include only if dilutive.
Contingent share rules (ASC 260-10-45-13): include in WASO when all conditions are satisfied.

Anti-dilutive securities excluded. Footnote discloses excluded amounts.

12. Hedge accounting (ASC 815 / IFRS 9)

Default treatment for derivatives: fair value through P&L. This injects volatility from instruments held to reduce risk. Hedge accounting realigns P&L recognition:

12.1 Fair value hedges

Hedge of FV exposure of recognized asset/liability or unrecognized firm commitment.

Hedged item: FV adjustment to carrying amount; gain/loss to P&L.
Hedging derivative: gain/loss to P&L.
Offset matches in same line (typically interest expense for rate hedges).

12.2 Cash flow hedges

Hedge of variability in future cash flows (forecasted purchases, floating-rate interest).

Effective portion: deferred in OCI, recycled to P&L when hedged forecast affects earnings.
Ineffective portion: P&L immediately (ASU 2017-12 simplified — generally now all to OCI for designated hedges; reclass to P&L on hedged item).

12.3 Net investment hedges

Hedge of FX exposure on net investment in foreign operation. FX gain/loss on derivative recorded in OCI (Cumulative Translation Adjustment).

Hedge documentation, designation, and ongoing effectiveness assessment required at inception and quarterly. ASU 2017-12 relaxed quantitative effectiveness thresholds significantly.

13. Financial ratios — the analyst’s toolkit

13.1 Liquidity

Current ratio = Current assets / Current liabilities. >1.0 generally healthy; sector-dependent.
Quick (acid-test) ratio = (Cash + Marketable securities + AR) / Current liabilities. Excludes inventory.
Cash ratio = (Cash + Marketable securities) / Current liabilities.
Working capital = CA − CL. Operating working capital strips out cash and short-term debt.

13.2 Solvency / leverage

Debt-to-equity (D/E) = Total debt / Equity. Book or market.
Debt-to-assets, Debt-to-EBITDA (covenant favorite; 3.0–4.0x typical IG, 5.0–7.0x HY).
Interest coverage (Times Interest Earned) = EBIT / Interest expense. >5.0x generally IG.
Fixed charge coverage = (EBIT + lease expense) / (Interest + lease expense).
Net debt = Total debt − Cash. Used in EV computation.

13.3 Profitability

Gross margin = Gross profit / Revenue.
Operating margin = Operating income / Revenue.
Net margin = NI / Revenue.
EBITDA margin = (Operating income + D&A) / Revenue. Non-GAAP; widely reported.
ROA = NI / Average total assets.
ROE = NI / Average equity.
ROIC = NOPAT / Invested capital (Debt + Equity − Cash) = EBIT(1−t) / (D+E−Cash).
DuPont decomposition (5-step):

ROE = (NI / Pre-tax income) × (Pre-tax income / EBIT) × (EBIT / Sales) × (Sales / Assets) × (Assets / Equity) = Tax burden × Interest burden × Operating margin × Asset turnover × Equity multiplier (leverage)

The 3-step simplification: ROE = Net margin × Asset turnover × Equity multiplier.

13.4 Efficiency / working capital

Asset turnover = Sales / Average assets.
Inventory turnover = COGS / Average inventory; DIO (Days Inventory Outstanding) = 365 / Inventory turnover.
Receivables turnover = Sales / Average AR; DSO (Days Sales Outstanding) = 365 / Receivables turnover.
Payables turnover = Purchases (or COGS) / Average AP; DPO (Days Payable Outstanding) = 365 / Payables turnover.
Cash Conversion Cycle (CCC) = DIO + DSO − DPO. Days between cash out (inventory paid) and cash in (collected from customers). Famous negatives: Amazon, Apple, Costco — collect before paying suppliers.

13.5 Valuation

P/E: Price / EPS — trailing, forward, NTM. CAPE (Cyclically Adjusted P/E) uses 10-yr smoothed real earnings (Shiller).
P/B: Price / Book value per share.
EV/EBITDA: capital-structure-neutral; banks/insurance exclude.
EV/Sales: when earnings negative.
FCF yield = FCF / Market cap.
Dividend yield = Annualized dividend / Price.

14. Audit — external, internal, and governance

14.1 The Big Four (and below)

PwC (PricewaterhouseCoopers) — Price Waterhouse + Coopers & Lybrand 1998 merger.
Deloitte — Touche Ross + Deloitte Haskins & Sells 1989.
EY (Ernst & Young) — 1989 merger of Ernst & Whinney + Arthur Young.
KPMG — 1987 merger of KMG + Peat Marwick.

Together they audit ~99% of S&P 500 and ~80% of all SEC registrants. Combined global revenue ~$200B (FY24).

Mid-tier: BDO USA, Grant Thornton, RSM US, Mazars (now Forvis Mazars after the BKD/DHG merger), Crowe, CohnReznick, Baker Tilly, Moss Adams.

Arthur Andersen — the fifth pillar, destroyed 2002 in the Enron aftermath; obstruction-of-justice conviction (overturned by SCOTUS 2005 but firm already gone).

14.2 Audit opinion types

Unqualified (“clean”): financial statements present fairly in all material respects.
Qualified (“except for”): one or more items improperly stated but rest fair.
Adverse: financials don’t present fairly. Rare; usually triggers delisting consideration.
Disclaimer of opinion: auditor unable to form an opinion (scope limitation).

14.3 PCAOB AS 3101 — Critical Audit Matters (CAMs)

Effective 2019 for large accelerated filers, 2020 for others. CAMs are matters communicated to audit committee that involve especially challenging, subjective, or complex auditor judgment. Each CAM disclosed in the audit report with description + how the auditor addressed it. Common CAMs: goodwill impairment, revenue recognition complexity, income tax provisions, business combination valuations, cyber-incident accounting.

14.4 ICFR — Internal Control over Financial Reporting

SOX §302: CEO + CFO personally certify financial statements’ accuracy and effectiveness of disclosure controls.

SOX §404: management asserts effectiveness of ICFR (404(a)); auditor attests independently (404(b)) for accelerated filers. The COSO framework is the de facto control framework (US).

Material weakness: deficiency where there is reasonable possibility of material misstatement not being prevented/detected. Public disclosure required; share price typically falls 5–15% on first-time disclosure.

14.5 Internal audit

Reports administratively to CFO/CEO, functionally to audit committee. Risk-based annual plan. IIA (Institute of Internal Auditors) publishes International Professional Practices Framework (IPPF).

14.6 Going concern

ASC 205-40 (effective 2017) / ISA 570: management evaluates ability to continue as a going concern for 12 months from issuance date; auditor evaluates independently. Substantial doubt requires disclosure + auditor going-concern paragraph. Notable triggers: covenant breach risk, recurring losses, negative cash flow, near-term debt maturities without committed refinancing.

15. COSO and internal control frameworks

COSO (Committee of Sponsoring Organizations of the Treadway Commission, originally 1985) issued the seminal Internal Control — Integrated Framework (1992, revised 2013). Five components:

Control environment (“tone at the top” — integrity, ethics, board oversight, structure, competence, accountability).
Risk assessment (objectives, risk identification, change management, fraud risk).
Control activities (preventive + detective controls; segregation of duties; authorization; reconciliations; physical safeguards).
Information and communication (relevant quality information; internal + external comms).
Monitoring activities (ongoing + separate evaluations; deficiency reporting).

17 principles operationalize the five components.

COSO also publishes the Enterprise Risk Management (ERM) Framework — Integrating with Strategy and Performance (2017).

IT controls: ITGCs (Information Technology General Controls) — access management, change management, computer operations, system development. ITACs (IT Application Controls) — embedded validations, calculations, interfaces. PCAOB AS 2201 makes IT controls integral to ICFR audit.

16. Forensic accounting and fraud detection

16.1 The classics

Year	Company	Fraud	Magnitude
2001	Enron	Off-balance-sheet SPEs (LJM, Raptors, JEDI), mark-to-market hubris, bogus broadband partnerships	$74B market cap evaporation; bankrupt Dec 2001. Drove SOX 2002. Arthur Andersen destroyed. Skilling, Lay, Fastow convicted.
2002	WorldCom	Capitalized $11 B o f l in ecos t s t ha t s h o u l d ha v e b ee n o p e x (a l so$ 3.8B in accruals manipulation)	Largest US bankruptcy at the time. Bernie Ebbers convicted 2005.
2002	Tyco International	Dennis Kozlowski + Mark Swartz looted ~$600M via unauthorized bonuses/loans	Both convicted 2005.
2003	HealthSouth	$2.7B inflated earnings 1996–2002	Richard Scrushy acquitted criminally (rare), found liable civilly.
2002	Adelphia Communications	Rigas family used company as personal piggy bank; concealed debt	John Rigas convicted; bankrupt.
2003	Parmalat (Italy)	€14B black hole; forged Bank of America certificate of deposit	Calisto Tanzi convicted; “Europe’s Enron.”
2008	Bernie Madoff	Largest Ponzi scheme in history — $65 B n o t i o na l ($ 17–20B actual losses)	150-year sentence. SEC failed to detect despite tips.
2008	Satyam Computer Services (India)	$1B+ inflated cash; founder Ramalinga Raju confessed in 2009 letter	”India’s Enron.”
2011	Olympus Corporation (Japan)	~$1.7B hidden investment losses (tobashi scheme) from 1990s; uncovered by CEO Michael Woodford and forced firing	Tsuyoshi Kikukawa convicted.
2015	Toshiba (Japan)	$1.2B+ overstated profits across multiple business units	Three CEOs resigned.
2015	Volkswagen	Diesel emissions (“Dieselgate”) — non-financial accounting fraud but reportable contingency	$30B+ in fines, settlements, recalls.
2020	Wirecard AG (Germany)	€1.9B missing cash from Asian “trust accounts” that never existed	DAX-listed; insolvency Jun 2020; CEO Markus Braun arrested. EY signed off for years.
2021	Greensill Capital	Supply-chain finance fund with circular invoice financing; brought down Credit Suisse Asset Management’s $10B fund	Lex Greensill under investigation.
2022	FTX / Alameda Research	$8B+ customer-fund commingling; phantom collateral; FTT inflated balance sheet	SBF (Sam Bankman-Fried) convicted Nov 2023 on 7 counts; 25-year sentence Mar 2024.

16.2 Quantitative fraud detection

Benford’s Law: in many natural datasets, the leading digit is distributed log-uniform (1 appears ~30.1%, 2 ~17.6%, …, 9 ~4.6%). Anomalous deviation in financial line items can flag manipulation. Used in regulatory and forensic engagements.
Beneish M-score (1999): 8-variable model (DSRI, GMI, AQI, SGI, DEPI, SGAI, LVGI, TATA). Score > −1.78 suggests likely earnings manipulator. Beneish flagged Enron in 1998.
Altman Z-score (1968): bankruptcy-prediction model. Z = 1.2·(WC/A) + 1.4·(RE/A) + 3.3·(EBIT/A) + 0.6·(MV equity/BV debt) + 1.0·(Sales/A). Z < 1.81 → distress zone.
Dechow F-score (Dechow-Ge-Larson-Sloan 2011): predicts material misstatement. RSST accruals + ΔAR + Δinventory + soft assets + Δsales + Δemployees variables.
Whistleblower programs:
- SEC Office of the Whistleblower (Dodd-Frank §922, 2010): 10–30% of sanctions over $1 Mp ai d t o q u a l i f y in g t i p s t ers . L a r g es t s in g l e a w a r d :$ 279M (May 2023, related to Ericsson).
- CFTC Whistleblower Program (similar).
- IRS Whistleblower Office (since 2006) for tax fraud.

16.3 ACFE Report to the Nations

The Association of Certified Fraud Examiners publishes biennial occupational-fraud study. Median loss per scheme ~$117k; typical detection time ~12 months; tips are #1 detection method (~43%); internal audit ~16%; management review ~12%. Owners/executives commit smaller-volume but higher-loss schemes than rank-and-file employees.

17. ESG and sustainability reporting

17.1 Frameworks

GRI (Global Reporting Initiative, 1997): broadest stakeholder framework; topic-specific standards.
SASB (Sustainability Accounting Standards Board, 2011): industry-specific, investor-focused. Merged into IFRS Foundation’s ISSB (International Sustainability Standards Board) 2022.
TCFD (Task Force on Climate-related Financial Disclosures, FSB 2017): governance, strategy, risk management, metrics & targets. Disbanded 2024 with framework absorbed into ISSB.
ISSB / IFRS S1 and S2 (effective Jan 2024): IFRS S1 (general sustainability disclosure), IFRS S2 (climate-specific). Voluntary except where adopted by jurisdictions; >25 countries committed.
EU CSRD (Corporate Sustainability Reporting Directive, effective FY2024 large companies → 2025–2028 wider rollout): ESRS standards. Double materiality (impact + financial).
EU SFDR (Sustainable Finance Disclosure Regulation): fund-product disclosure (Article 6/8/9 classification).
SEC Climate Rule (March 2024 final): scaled-back from 2022 proposal; paused April 2024 under Eighth Circuit litigation; status uncertain pending administrative review.
California SB 253 & SB 261 (2023): Scope 1+2 and Scope 3 GHG disclosure for large companies operating in CA. SB 253 covers > $1 B re v e n u e; SB 261 co v ers >$ 500M.

17.2 Assurance

ESG reporting increasingly subject to assurance — limited (review-level) initially, transitioning to reasonable (audit-level). Big Four expanding sustainability assurance practices (acquisitions: PwC purchased multiple boutiques; Deloitte’s ESG service line; EY Carbon).

18. Accounting software and ERP

18.1 Enterprise ERPs

SAP S/4HANA — German; dominant in Fortune 500 manufacturing/industrial. ECC retiring 2027 (extended to 2030 via SAP Premium Engagement).
Oracle Fusion Cloud ERP + NetSuite (Oracle acquired 2016, ~$9.3B) for mid-market.
Workday Financial Management — cloud-native, strong in services/healthcare/higher ed (originally HR/Payroll champion).
Microsoft Dynamics 365 Finance + Business Central.
Infor, Epicor, IFS in vertical niches.

18.2 Mid-market and SMB

NetSuite — ~40k customers; cloud-native multi-entity.
Sage Intacct — financial-only mid-market cloud.
QuickBooks Online / Desktop (Intuit) — dominant US SMB (~5M+ subscribers).
Xero — Australian/NZ origin, strong UK + AU presence; ~4M subscribers.
FreshBooks, Wave (free, accepted by Square→Block then divested 2022), Zoho Books.

18.3 ERP modules

Standard suite:

GL (General Ledger) — chart of accounts, journal entries.
AR (Accounts Receivable) — billing, collections, credit management.
AP (Accounts Payable) — vendor invoicing, three-way match (PO + GR + invoice), payment runs.
FA (Fixed Assets) — depreciation schedules, additions, disposals.
Inventory — perpetual costing, cycle counts, valuation methods.
Payroll — gross-to-net, tax filings, integrations (ADP, Paychex, Gusto, Rippling).
Treasury — cash position, bank reconciliation, FX, hedging.
Project accounting / WIP — services billing, milestone tracking.
Procurement — sourcing, contract management.
Consolidation & reporting — OneStream, Workiva Wdesk, Oracle Hyperion, SAP Group Reporting.

18.4 Add-ons that matter

Lease accounting: LeaseQuery (FinQuery), LeaseAccelerator, Visual Lease, Nakisa, AMTdirect.
Revenue recognition: Zuora RevPro, SAP RAR, Sage Intacct ASC 606, Salesforce Revenue Cloud.
SOX / GRC: AuditBoard, Workiva, MetricStream, ServiceNow GRC, OneTrust.
Tax provision: ONESOURCE (Thomson Reuters), CorpTax, Oracle Tax Reporting Cloud.
Audit automation: CaseWare, MindBridge AI, AppZen, Mintz Group, Datasnipper (Excel add-in popular post-2020).
AP automation: Bill.com, Tipalti, Stampli, AvidXchange, Coupa.
Spend management: Coupa, Ariba (SAP), Procurify, Ramp, Brex, Airbase.

19. Professional credentials

CPA (Certified Public Accountant, US): state-by-state license; AICPA Uniform CPA Exam (FAR, AUD, REG, plus discipline choice — BAR/ISC/TCP under new Evolution model effective 2024); 150 credit hours + experience.
CA / Chartered Accountant: UK (ICAEW, ICAS), Ireland (CAI), India (ICAI), Australia + NZ (CA ANZ), Canada (CPA Canada — merged the three legacy bodies CA/CMA/CGA in 2014).
ACCA (Association of Chartered Certified Accountants, UK-based, global).
CMA (Certified Management Accountant, IMA): managerial/cost focus.
CIA (Certified Internal Auditor, IIA).
CISA (Certified Information Systems Auditor, ISACA) — IT audit.
CFE (Certified Fraud Examiner, ACFE).
CFA (Chartered Financial Analyst, CFA Institute) — investment focus; covered in investments-and-portfolio-management.
EA (Enrolled Agent, IRS) — federal tax representation rights.

20. Open issues and contemporary debates

Non-GAAP measures: adjusted EBITDA, free cash flow, organic revenue. Reg G + Item 10(e) require GAAP reconciliation and prohibit greater prominence to non-GAAP. SEC routinely challenges misleading exclusions (recurring restructuring, “non-recurring” items that recur, individually-tailored revenue measures).
Stock-based comp in non-GAAP earnings: heavily contested. Buffett: “If compensation isn’t an expense, what is it? And if expenses shouldn’t go into the calculation of earnings, where in the world should they go?”
Crypto accounting (ASU 2023-08 effective FY2025): fair value through P&L for crypto assets meeting scope (BTC, ETH, etc. as standalone fungible). Replaces prior indefinite-life intangible with impairment-only model. MicroStrategy and Tesla among first reporters under new standard.
AI in close & reporting: GenAI copilots (Microsoft Copilot in Excel/Dynamics; Vic.ai; Klarity; Trullion; Auditoria) accelerating reconciliations, journal-entry classification, contract review for revenue recognition. Audit firms (PwC, Deloitte, EY, KPMG) investing heavily.
Climate accounting: provisions for emissions liabilities, asset retirement obligations on stranded fossil-fuel assets, carbon-credit accounting (no specific GAAP/IFRS standard yet — diverse practice).
Cloud computing costs: ASU 2018-15 — capitalize implementation costs of CCAs (cloud computing arrangements) by analogy to internal-use software (ASC 350-40). Major change for SaaS-heavy enterprises.

Adjacent

corporate-finance-and-markets — capital structure, dividend policy, M&A, IPO mechanics; relies on accounting foundations for valuation inputs.
investments-and-portfolio-management — equity valuation methods (DCF, comps) require accounting fluency; financial-statement analysis is core to security selection.
derivatives-and-quant-finance — hedge accounting under ASC 815 / IFRS 9 is the accounting overlay on derivatives risk management.
microeconomics — firm theory, cost curves, and producer behavior underpin managerial accounting.
securities-and-corporate-law — ‘33 Act, ‘34 Act, SOX, Dodd-Frank framework around public-company financial reporting and auditor independence.
probability-and-statistics — regression and hypothesis testing methods used in actuarial pension assumptions, ECL/CECL modeling, and forensic analytics.
data-engineering — ERP data models, ledger systems, ETL into reporting/BI tools; closing process automation.

Compendium

Explorer

Accounting Foundations — GAAP/IFRS, Statements, Ratios, Auditing