Ownership Blockers: Why 4.99% and 9.99% Caps Do Not Limit Total Dilution

The short version

An ownership blocker, also called a beneficial ownership limitation, is a clause in a warrant, convertible note or convertible preferred stock that stops the holder from converting or exercising if doing so would push its stake above a set percentage of the company's outstanding shares. The usual figures are 4.99% and 9.99%.

It sounds protective, and in one narrow sense it is: no single holder can suddenly become a large controlling shareholder through conversion. But a blocker caps how much the holder owns at one moment. It does not cap how many shares the holder can receive over time. A holder that converts up to the limit, sells those shares, and converts again can work through the entire instrument while never crossing the threshold.

Why the thresholds are 4.99% and 9.99%

The numbers are not arbitrary. They sit just under two regulatory lines in US securities law:

• 5%: crossing it triggers a Schedule 13D or 13G beneficial ownership filing under Section 13(d) of the Securities Exchange Act, which publicly discloses the holder's stake and, for a 13D, its intentions.
• 10%: crossing it makes the holder an insider under Section 16, which brings Form 4 reporting of every trade and the short-swing profit rule, under which profits from a purchase and sale within six months can be recoverable by the company.

Staying at 4.99% or 9.99% keeps a holder out of those regimes. It also matters for resale: a holder that is not an affiliate can often sell shares under Rule 144 more freely than one that is.

How the clause reads in a real prospectus

Blockers appear on many pre-funded warrants, which are warrants with a nominal exercise price sold in place of common shares. A prospectus supplement on Form 424B5 filed on 2026-09-30 (accession 0001193125-26-407980) described pre-funded warrants that:

may be exercised at any time until exercised in full, subject to the limitation that exercise may not result in the investor's beneficial ownership exceeding 4.99% (or, at the election of the investor, 9.99%) of our outstanding shares of Class A Common Stock.

That is a typical formulation. Many agreements add that the holder can raise the limit (often up to 9.99%) on 61 days' notice, so the lower figure is not always fixed.

A worked convert-and-sell cycle

Hypothetical Company X has 20,000,000 shares outstanding. An investor holds a convertible note that converts into 6,000,000 shares in total, which is 30% of the current share count. The note has a 4.99% blocker. The investor starts with no common shares.

Each round, the investor converts the maximum allowed (enough to reach 4.99% of the new total), then sells all of those shares before the next round.

All figures hypothetical and rounded.

At no point did the investor own more than 4.99%. Yet the full 6,000,000 shares entered the market, and the share count grew by 30%. Every other holder was diluted exactly as much as they would have been with no blocker at all.

Why the blocker can increase selling pressure

A holder without a blocker could convert everything at once and hold a 23% stake. A holder with a blocker is pushed toward selling in order to keep converting, because the only way to make room under the cap is to reduce the position. Whether a holder actually sells, and how fast, is a business decision the filings do not predict. The structural point is that a blocker does not reduce supply; at most it spreads it out.

This interacts badly with variable-price terms. On a floorless convertible, selling between rounds can lower the reference price used for the next conversion, which increases the shares per dollar converted. That combination is one reason these clauses are discussed together under the vernacular label toxic financing, which names the deal structures rather than any party to them.

Blockers hide holders from the usual ownership data

Because the holder stays under 5%, it may never file a Schedule 13D or 13G for that position, and because it is not a 10% holder it files no Form 4. If it is not an institutional manager over the reporting threshold, it may not appear in a 13F either. The investor's identity is still disclosed in the financing documents, but it can be absent from ownership tables and screeners built on 13D, 13G, 13F and Form 4 data.

Several separate entities affiliated with one sponsor can each hold up to the limit, and agreements sometimes aggregate "Attribution Parties" to prevent that. Check the definition.

What to look for in the filings

• The phrases "Beneficial Ownership Limitation", "Maximum Percentage", "4.99%", "9.99%", "61 days' prior notice" and "Attribution Parties".
• Whether the limit is fixed or can be raised by the holder, and to what maximum.
• Whether the limit applies to conversion only, or also to shares received as interest or dividends.
• In the selling shareholder table of a resale S-1 or S-3, footnotes explaining that the "shares beneficially owned" column is limited by the blocker while the "shares offered" column is not. That difference is the clearest written statement of how many shares are really coming.

How to check a company on Signal8

• On a company's Dilution tab (example), convertibles extracted from filings can carry an Ownership blocker chip when the terms include one, alongside other structural chips such as No conversion floor. The chips describe disclosed terms only. Coverage focuses on small caps and varies by company.
• The insider trades page shows Form 4 activity, which is useful precisely because a blocked holder usually does not appear there.
• The dilution screener compares dilution-related data across companies.

FAQ

Does a 4.99% blocker limit how many shares a company can issue to one investor?

No. It limits how much of the company the investor can own at any single moment. If the investor sells shares it already holds, it regains room under the cap and can convert or exercise again. Over time, the whole instrument can be converted into shares while the investor's stake never exceeds 4.99%.

Why do so many warrants and notes include a 9.99% option?

Moving from 4.99% to 9.99% lets a holder convert larger chunks at a time while still staying under the 10% line that would make it a Section 16 insider subject to Form 4 reporting and the short-swing profit rule. Agreements often require advance notice, commonly 61 days, before the higher limit takes effect.

Can a blocker be waived?

Usually the holder can raise or lower the limit within a stated range, and lowering is typically immediate. Raising beyond the stated maximum generally requires an amendment, which a company would normally disclose. Read the specific clause, because some limits can be waived only at issuance.

How do I estimate total dilution when a blocker is present?

Ignore the blocker for that purpose. Use the total shares issuable under the instrument: for a fixed-price note, outstanding principal divided by the conversion price; for a variable-price note, a range of hypothetical prices. The blocker affects the pace and the holder's reporting status, not the total.