What managers hid, and what they were hiding

A manager building a large position can ask the SEC to keep it out of the public 13F, on the argument that disclosure while they are still buying would move the price against them. When the grant lapses they file an amendment adding the positions back. That amendment is the disclosure, and it is the only public record of what was being accumulated in the dark.

Disclosed late

Amendments that added holdings at least 120 days after the quarter they cover. A 13F is due 45 days after quarter end and an ordinary correction follows within weeks, so a much later addition is a grant expiring. The lag is how long the market did not know. Filings adding more than 100 positions are left out - that is a manager refiling an entire book rather than revealing a withheld holding.

Values before 2023 are shown as not comparable: filers reported in thousands until then and these amendments never went through the correction, so the figures would be a thousandfold too large.

Withholding right now

These managers filed a 13F whose cover page states that holdings have been omitted under confidential treatment. What is missing becomes public when the grant lapses, usually within a year, and appears in the table above when it does.