Coverage & Stability
Every holdings-derived answer carries two numbers alongside it. They are not diagnostics for the maintainer — they are how you tell a strong claim from a weak one.
Coverage
The share of a fund's disclosed weight that could be classified into the sector or market being reported.
A 60% sector weight at 0.3 coverage is a much weaker claim than the same weight at 0.95.
Coverage drops when instrument enrichment could not resolve a position — an uncovered symbol, a listing Yahoo does not carry, or a classification pass that hit its deadline before reaching every holding.
Holdings stability
How much of the previous report the fund still holds.
- Index funds sit near 1.0.
- A low score means last quarter's portfolio no longer describes the fund, and its inferred exposure should be discounted accordingly.
An exposure vector is a snapshot of a disclosure, not a live portfolio. Stability is the measure of how much that snapshot is still worth.
Disclosure completeness
A third property, recorded per fund as holdings_completeness:
| Value | Meaning |
|---|---|
full | Weights cover the fund's whole book |
top_holdings | Only the largest positions are disclosed |
Tool responses carry a note derived from it, and a result mixing both conventions gets an explicit warning. Ranking funds by a disclosed sector weight across conventions measures reporting rules, not portfolios.
This is also why fundsByHoldings results should be ranked by shareOfDisclosedPercent rather than matchedWeightPercent: a share of net assets is structurally smaller for a fund that discloses only its top ten.
Mandates do not drift
themeToFunds reports index-tracking matches separately from holdings-derived ones for the same reason. A declared mandate is a stable fact about a fund; a holdings snapshot is a measurement with an age and an error bar.