XBRL Fallbacks

XBRL coverage is incomplete. Many real issuers — especially the small-cap
universe where dilution analysis matters most — return either 404 or
empty datapoints from data.sec.gov/api/xbrl/companyfacts/CIK*.json.
Treating absence of XBRL as absence of data is a quant pipeline bug.
The shares-outstanding number is almost always somewhere; just not
in the structured feed.

Core principle

XBRL is one source, not the source. When the structured feed is
sparse or missing, the same datapoint is recoverable by reading the
filing's text — typically the cover page or an early section of the
prospectus. Build the fallback path explicitly into the pipeline; don't
treat XBRL 404 as "no data".

When XBRL fails (the 404 / empty-set universe)

1. Recent FPIs (Foreign Private Issuers). They file F-1, 20-F, 6-K
   in HTML/PDF. XBRL coverage is often delayed, partial, or absent for
   years after IPO. Common in Chinese small-cap IPOs (-F suffix CIKs,
   recent listings on Nasdaq Capital Market).
2. Recent US IPOs in the first 2 quarters post-listing — 10-Q
   XBRL exists but the cover-page share count may be the only reliable
   datapoint until the second 10-K is filed.
3. SPACs pre-business-combination. The shell phase has minimal
   XBRL; cover-page counts on the most recent 10-Q/10-K govern.
4. Shell companies / OTC issuers where XBRL is filed late or only
   for the most recent period.
5. Amended filings (10-K/A, 10-Q/A) — sometimes don't republish
   XBRL; you have to read the amendment text.

Fallback hierarchy

When XBRL is missing or stale, search for shares-outstanding in this
order:

1. Most recent 10-Q cover page (US issuer) — "As of [date], the
   registrant had [N] shares of common stock, $[par] par value, outstanding."
2. Most recent 10-K cover page (US issuer) — same pattern, slightly
   different timing (annual).
3. Most recent 6-K cover or text (FPI) — variable format; often
   reports issuance counts within the body. Look for "ordinary shares"
   or "common shares" + "issued and outstanding".
4. Most recent 20-F cover (FPI annual) — formal cover-page
   statement near the registrant block.
5. Most recent F-1 / F-3 / F-3A cover or first page (FPI registration).
6. Most recent 424B prospectus supplement cover — discloses
   pre-offering share count and post-offering count.
7. Most recent DEF 14A (proxy) — record-date count, useful as
   a sanity check.
8. Form 10 / S-1 (if newly registering) — initial count.

The earliest plausible source wins; later sources are sanity checks.
Always record which source was used.

Extraction patterns (text-based)

Cover-page share-count language is heavily templated. The common forms:

• "As of [date], [N] shares of [class] common stock were outstanding."
• "[N] shares of common stock, par value $[X] per share, are issued
  and outstanding as of [date]."
• "[N] ordinary shares" / "[N] American Depositary Shares (ADSs)"
  representing [M] ordinary shares (FPI ADR structure — keep BOTH
  numbers and note the ratio).
• "[N] Class A common stock and [M] Class B common stock"
  (multi-class issuers — sum carefully or track per-class).
• "issued and outstanding": [N] (table format common in proxies).

Numbers may be expressed with commas, no commas, or scaled
("12.3 million" / "12,300,000"). Always normalize to integer share
count and record the as-of date.

Multi-class share gotchas

Many small-cap FPIs and biotech reorganizations have multiple share
classes. Treating "common stock outstanding" as a single number can be
wrong by a factor of 2–10x.

• Class A / Class B: voting/economic asymmetry — sum for total
  outstanding but track separately for control analysis.
• Ordinary shares + ADSs: FPI structure. ADSs trade on the US
  exchange but represent ordinary shares at a ratio (often 1:10 or
  1:50). Float-rotation math must use the ADS-equivalent count, not
  the underlying ordinary share count.
• Preferred convertible into common: not currently outstanding as
  common but creates shadow dilution. Note as a separate line.

Synthetic-tag convention (for pipelines)

When emitting fallback data into a downstream system that expects XBRL
shape, use a synthetic tag namespace to preserve provenance:

{
  "tag": "text:SharesOutstanding",
  "value": 23300000,
  "source_form": "424B4",
  "source_accession": "0001213900-24-XXXXXX",
  "as_of_date": "2024-09-15",
  "filed_date": "2024-09-18",
  "confidence": "medium"
}

text: prefix distinguishes from real XBRL (us-gaap:, dei:,
ifrs-full:). Confidence reflects parsing precision (e.g.,
"high" = direct quote, "medium" = inferred from context, "low" =
calculated from offering deltas).

Validation rules

1. The fallback datapoint's filed_date must obey lookahead-safety
   — never use as_of_date as the known-date.
2. Cross-check the fallback against ANY available XBRL — even one
   datapoint can confirm the order of magnitude.
3. Sanity-check against the offering history: if the issuer raised
   N shares between two cover-page disclosures, the difference between
   the two counts should be approximately N (modulo buybacks, splits,
   exercises).
4. Flag any fallback as text: and surface the source filing in the
   final output — don't silently treat it as XBRL-quality.

Workflow when XBRL returns 404 or empty

1. Confirm the CIK is correct (most common false-404 cause is a CIK
   typo or unmapped ticker — see cik-resolution if available).
2. Pull the issuer's full submissions list:
   data.sec.gov/submissions/CIK{padded}.json
3. Walk filings in REVERSE chronological order through the hierarchy
   above (10-Q → 10-K → 6-K → 20-F → F-* → 424B → DEF 14A).
4. Extract the cover-page count from the FIRST filing that has it.
5. For historical analysis, walk forward from the earliest fallback
   datapoint, applying offering deltas (424B / 8-K item 3.02) between
   stamps to maintain a continuous timeline.
6. Tag every fallback datapoint with source attribution and confidence.

Phrases that should trigger this skill

• "XBRL is empty / missing / 404"
• "no XBRL for ticker X"
• "FPI shares outstanding" / "Chinese small cap shares outstanding"
• "20-F" / "6-K" / "F-1" + share count
• "ADS to ordinary shares ratio"
• "cover page shares"
• "how do I get shares outstanding without XBRL"
• "SPAC shares outstanding"

What this skill is NOT

This is not a regex library or extractor. It defines the source
hierarchy and validation rules so the LLM (or pipeline) can decide
WHERE to look and HOW to attribute the result. Combine with
lookahead-safety for time semantics and sec-filing-types for
form-by-form context.