Schedule 13D is the SEC filing an investor must submit after acquiring more than 5% of a public company's voting shares with intent to influence or control it — disclosing the stake, intent, and funding, within five business days.
A 13D is the "activist" filing. Crossing 5% of a voting class with any purpose other than passive investment triggers it, and the filer must lay out who they are, how much they own, how they paid for it, and — critically — their plans for the company (board seats, a sale, a strategy change).
Since the SEC's 2024 amendments, the initial 13D is due within five business days of crossing the threshold (previously ten calendar days), with amendments required "promptly" on material changes. The cheaper, lower-deadline alternative for genuinely passive holders is Schedule 13G.
An activist fund buys 6% of a company and files a 13D stating it intends to push for board representation and a strategic review.
13D/G is the next layer of the EDGAR ownership cluster — it captures control intent that 13F (positions only) and Form 4 (insiders only) miss.
Arkolith turns this into live, sourced data your agent can query — SEC filings, insider activity, and market data behind one key, every datapoint traceable to its origin.