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  3. SEC Filings

Schedule 13D

M
Marcus Thorne
Last Updated: January 5, 2026
Plain English Definition

Schedule 13D is known as the "Beneficial Ownership Report." It must be filed when a person or group acquires more than 5% of any class of a company's equity securities with the intent to influence or change control.

The Trader's Take

The Signal

Extremely Bullish/Volatile. This is the "Activist Investor" filing. It often precedes a takeover attempt or major corporate overhaul.

The Noise

Rarely noise. Any 13D filing is a major market event.

Actionable Insights

  • 1
    Read the "Purpose of Transaction" (Item 4) carefully.
  • 2
    Track the "Group" members to see if other whales are joining the position.
  • 3
    Watch for 13D/A (amendments) which signal the activist is buying more or changing their demands.

Regulatory Context & Context

Often called the "Williams Act," it prevents "creeping" takeovers by forcing large buyers to disclose their identity and intentions once they cross the 5% threshold.

Common Misconceptions

It is different from 13G, which is for passive investors.

Crossing 5% doesn't make you an "insider" (officer/director), but it does subject you to Section 16 rules if you cross 10%.

Frequently Asked Questions

What is the 13D filing deadline?

Within 5 business days of crossing the 5% threshold.

On This Page

Trader's TakeRegulatory ContextCommon MisconceptionsF.A.Q.

Related Intelligence

SEC Filings
Schedule 13G
Trading Terms
Beneficial Owner
SEC Filings
Form 4

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