The 45-day delay, and how to think about stale data

Filings describe a quarter that ended weeks ago. Here is what that does and doesn't invalidate.

A 13F for the quarter ending June 30 can legally be filed any time through mid-August, and most managers use most of the window. By the time the data is public, it is six to nineteen weeks old. Does that make it worthless? No — but it changes what questions the data can answer.

Questions the delay ruins

"What does this fund own today?" — unanswerable from a 13F. Fast-turning managers (quantitative funds, multi-manager platforms) can rotate a large share of their book inside a quarter, so a single stale snapshot of a fast trader carries little information about the present.

Questions the delay barely touches

"Is institutional ownership of this company broadening or narrowing over quarters?" — the delay shifts the window but not the trend. Slow-moving managers with multi-year holding periods are also well described by quarterly snapshots; when a manager's median holding period is three years, a 45-day-old picture is close to current.

That is why this site computes position persistence (consecutive quarters held, accumulation streaks) and shows every manager's activity profile: the same delay means different things for different managers, and the data itself tells you which kind you are looking at.

Filing-season dynamics

Because most managers file near the deadline, the picture assembles unevenly: early in a season, aggregates reflect whoever has filed, not the whole universe. Pages on this site show the comparable-universe count next to season-level claims, and the filing season page shows how complete the season is. Treat early-season aggregates as previews.