When a significant event occurs at a publicly traded company, federal law requires the firm to disclose this information to investors in a securities filing known as a Form 8-K. But the firm need not disclose immediately; instead, SEC rules give companies four business days after the event...

We show that the Securities and Exchange Commission's system for disseminating market-moving information in securities filings gives some investors an advantage over others. We describe two systems — the SEC's file transfer protocol (FTP) server and public dissemination service (PDS) — that...