underpayment

Machine-readable

Canonical IRI: https://lexicon.financial/ext/uscode/us/usc/t26/s6656/b/2

JSON-LD — schema.org/DefinedTerm structured data
N-Triples — RDF triples for ontology consumers
JSON — short row form (label, definition, source, license)

Lexicon — an open reference of financial, business, and legal terminology. Every definition carries its own license, shown on the block.

Sources & licenses

Source	License	Entries	Why we use it
FIBO	MIT	3,330 classes	Canonical financial ontology from the EDM Council — banking, securities, debt, corporate structure.
Lexicon extension (`lex:` / `dr:`)	MIT	62 classes	Curated M&A terms (Quality of Earnings, SDE, LOI, DSCR, BBS grade, Earnest Money, Purchase Agreement, Working Capital, Customer Concentration), Person / Dossier / Evidence / Collector (PROV-O subclasses), and ~30 cross-reference anchor concepts (Chapter 7/11/13, FIFO, GAAP, IFRS, FASB, PCAOB, etc.).
XBRL US-GAAP 2026	FAF royalty-free	17,182 elements (14,760 with documentation)	Every element FASB ships in its 2026 financial-reporting taxonomy — line-item names, abstract groupings, axes, members, types — pulled from `xbrl.fasb.org/us-gaap/2026/us-gaap-2026.zip`. Standard labels become pref labels; documentation linkbase prose becomes definitions; terse / total / period-start / period-end labels join as alt labels.
Plaid PFC Taxonomy	Published spec	120 categories (16 primary + 104 detail)	Plaid's transaction-categorization taxonomy. `INCOME_WAGES` survives as alt-label so downstream Plaid integrations can lookup canonically; pref label is the humanized leaf ("Wages"); detail rows are `rdfs:subClassOf` their primary.
GnuCash chart of accounts	MIT (paraphrased)	100 accounts (13 with definitions)	Account names + types from the GnuCash US chart templates (common + business). Names + type enums treated as facts; the GPL-tainted `act:description` strings are dropped and replaced with hand-paraphrased one-line definitions for ~30 well-known accounts (Cash, Accounts Receivable, Cost of Goods Sold, Depreciation, Retained Earnings, etc.) at `data/coa_definitions.jsonl`.
Wikidata — finance classes	CC0 1.0	752 classes	Pulled via SPARQL from `wdt:P279*` under `wd:Q43015` (finance) + `wd:Q650241` (financial institution). CC0 — no attribution burden.
schema.org	CC-BY-SA 3.0	1,007 classes	General business concepts (Organization, Product, LocalBusiness, Offer) — used across the open web, matches common consumer vocabulary.
NAICS 2022	US public domain	2,122 codes	The full Census NAICS hierarchy, sector through 6-digit industry — same codes brokers see on Schedule C. Each code links `rdfs:subClassOf` the level above; the numeric code doubles as an alt-label so `541211` matches "Offices of Certified Public Accountants".
Tryton account_us	GPLv3+ (paraphrased)	1,201 entries	The most US-GAAP-native account hierarchy in the OSS ecosystem — balance-sheet vs income-statement classification baked into account types. Names + types ingested as facts; no GPL-tainted prose mirrored.
BEA Glossary	US public domain	200 entries	Bureau of Economic Analysis terminology — national-accounts vocabulary (GDP components, NIPA structure, BEA-specific aggregates). Federal complement to BLS labor-market vocabulary.
BLS Glossary	US public domain	580 entries	Bureau of Labor Statistics glossary — labor-market terminology (employment, unemployment, payroll, wages, occupational classifications). Sourced via Wayback Machine snapshot since BLS Akamai infrastructure 403s direct fetches.
Open English WordNet 2024	CC-BY 4.0	578 alt-labels (synonym layer)	WordNet's finance-domain synsets layered as `skos:altLabel` rows on the existing corpus — adds e.g. "AR" / "trade receivables" alts alongside the canonical "Accounts Receivable". Filter: lexicographer file in `noun.act` / `noun.attribute` / `noun.cognition` / `noun.communication` / `noun.event` / `noun.group` / `noun.possession` / `noun.quantity` / `noun.relation` / `noun.state` AND definition matches a finance keyword regex.
FRED Categories	US public domain	669 categories	St. Louis Fed FRED API category taxonomy, top 3 levels — 8 top-level economic domains (Money/Banking/Finance, National Accounts, Prices, etc.) and their sub-categories down to specific measurement areas. Each category links `rdfs:subClassOf` its parent.
ERPNext charts	GPLv3 (paraphrased)	95 entries	Adds `account_number` ranges (1xxx Asset, 2xxx Liability, 4xxx Income, 5xxx Expense) and `account_category` labels that GnuCash and Tryton don't expose explicitly.
OFX 2.x TRNTYPE	Spec (facts)	17 enum values	The bank-statement transaction-type enumeration every U.S. bank-feed downloader uses — CREDIT / DEBIT / INT / DIV / FEE / DEP / ATM / POS / XFER / CHECK / PAYMENT / DIRECTDEP / DIRECTDEBIT / etc. Underneath Plaid's consumer categorization layer.
LKIF-Core	CC-BY 4.0	255 classes	Core legal concepts (roles, norms, actions, processes) from the EU ESTRELLA project — the most-cited open legal ontology.
U.S. Code Title 26 (Internal Revenue Code)	US public domain	1,143 definitions	Explicit "the term X means Y" definitions extracted from the USLM XML feed at uscode.house.gov — §7701 General Definitions plus 1,000+ scattered in-line definitions. Source-linked to Cornell LII.
IRS Publications 334 / 463 / 583	US public domain	21 definitions (hand-triaged from 75 candidates)	SMB-relevant terms inline-defined in the published HTML of IRS Pubs (Trade or business, Sole proprietor, Cash method, Accrual method, Section 179 deduction, Per diem rates, etc.). Triage rules + re-run instructions at `data/irs_triage_notes.md`.
W3C PROV-O	W3C Document License	49 classes (parents only)	Provenance ontology — used as the parent class hierarchy for the dealright-ext Person / Dossier / Evidence / Collector classes. No own page bucket; rendered as parent classes inside dealright-ext term pages.
Wikipedia — supplements	CC-BY-SA 3.0	586 hits	Encyclopedia-length summaries via the REST `/page/summary/` endpoint for richer context on complex concepts (CDOs, derivatives, etc.).
Wikidata — supplements	CC0 1.0	724 hits	One-line structured descriptions attached as an additional block on FIBO pages.
Wiktionary	CC-BY-SA 4.0	322 hits	Plain-language dictionary senses, appended as a supplement where FIBO's formal definition is too terse.
Investor.gov · CFTC · Federal Reserve	US public domain	1,205 entries (82 hits)	Authoritative US regulatory + banking glossaries scraped once into JSONL. Public domain — zero licensing friction.

Totals: 28,335 canonical terms across 17 source corpora. 1,718 supplementary definitions layered on top from Wiktionary, Wikipedia, Wikidata, and US glossaries. The XBRL US-GAAP 2026 taxonomy is by far the largest at 17,182 elements (14,760 with prose definitions from the FASB documentation linkbase).

Documented but not yet ingested: CFPB Consumer Financial Glossary (URL deprecated), FRO (Hoffman Financial Report Ontology — download URLs 404), Apache OFBiz GL accounts (current trunk only ships mappings, not master records), BLS Glossary (Akamai bot-block), FFIEC Call Report taxonomy (largely covered by GAAP B1), FDIC Money Smart for Small Business (PDF source), WordNet financial synonyms (synonym layer; needs WordNet data file), and the SEC DERA usage-rank signal for GAAP elements. Each deferred source has a stub loader at loader/load_<key>.py documenting the blocker and the resume path.

FAF Authorized Uses notice (required by the XBRL US-GAAP Taxonomy license): The US GAAP Financial Reporting Taxonomy may be used by the public, royalty-free, in reporting financial statements under U.S. GAAP, and may be incorporated without change, in whole or in part, in other works that comment on, explain, or assist in the use or implementation of the Taxonomy. Source: accountingfoundation.org/page/pageContent?pageId=/Termsofuse/Termsofuse.html.

Transformations applied to supplement text (disclosed per CC-BY-SA's attribution requirement): HTML tags and MediaWiki CSS are stripped, whitespace is collapsed, and for Wiktionary entries we select the first English noun sense. Labels are mechanically humanized (e.g. "cash c d o" → "cash CDO"). The unmodified source is always linked so you can compare.

Pages that embed CC-BY-SA content are themselves CC-BY-SA 4.0 (the ShareAlike clause). Pages containing only MIT / CC-BY / CC0 / US-public-domain content inherit the most-restrictive license among their blocks — typically MIT for pure FIBO pages.

Editorial scope & jurisdictional notes

U.S.-first orientation. Lexicon is built for U.S. small- and lower-middle-market M&A workflows. When multiple authoritative sources define the same concept, we rank U.S. anchors highest: FASB / XBRL US-GAAP for accounting line items, the IRC for tax, the SEC for disclosure, the U.S. Bankruptcy Code for insolvency. International sources (FIBO, IFRS, schema.org, Wikidata) are included for breadth but are not the primary reference for U.S.-domiciled deals.

IFRS is a foreign-issued standard. The International Financial Reporting Standards are issued by the IASB in London and used by 140+ jurisdictions, but U.S. domestic SEC registrants must file in U.S. GAAP. Specific IFRS recognition, measurement, and disclosure rules differ materially from U.S. GAAP — for example, LIFO inventory is permitted under U.S. GAAP but prohibited under IFRS, development costs are expensed under U.S. GAAP but capitalizable under IAS 38, and revaluation of PP&E is allowed under IFRS but barred under U.S. GAAP. We do not ingest the IFRS Glossary itself (the IFRS Foundation reserves its trademarks and the official glossary is licensed for personal use only); the Lexicon's `concept:IFRS` page is a U.S.-perspective summary, not a substitute for the IASB's authoritative text. Treat any IFRS-flavored term as informational and verify against U.S. GAAP before relying on it for a U.S. filer.

Why we license the way we do. Every definition is published under the most permissive license compatible with its source — facts (statutory definitions, enumerated codes, account numbers, taxonomy IRIs) are treated as uncopyrightable and re-published freely; prose definitions inherit their source's terms. We deliberately do NOT mirror GPL-tainted prose from GnuCash / Tryton / ERPNext (we ingest only the account names + types as facts and paraphrase any descriptions); CC-BY-SA content from Wiktionary / Wikipedia is republished under the same license and clearly attributed; CC0 / public-domain sources (Wikidata, FRED, BEA, BLS, IRC, IRS Pubs, NAICS, Investor.gov, CFTC, Federal Reserve) carry no attribution burden. The XBRL US-GAAP Taxonomy is republished under the FAF royalty-free terms reproduced above. Pages embedding CC-BY-SA content are themselves CC-BY-SA 4.0 by inheritance; everything else is MIT or the most-permissive license available among its blocks.

Not legal, tax, or investment advice. The definitions on this site are reference material — they are not legal advice, not tax advice, and not a substitute for consulting a licensed attorney, CPA, or financial advisor on a specific situation. Tax law and accounting standards change frequently; verify against the primary source linked on each block before relying on a definition for a real filing.

AI-assisted content. Label humanization, acronym extraction, and sense disambiguation were generated or reviewed by AI. AI can make mistakes — please verify anything you rely on.