Two Ceilings, One Nano Cap: Regulation A's $75 Million Limit Against Form S-3's One-Third-of-Float Cap

by Renée Delacroix · September 14, 2026

Senior Analyst, The MicroCap Herald

A US-listed company too small for the ordinary shelf has two federal routes to sell stock to the public, and each arrives with its own ceiling. One number lives in the General Instructions to Form S-3, the Securities and Exchange Commission's shelf registration form. The other lives in Rule 251(a) of Regulation A, at 17 CFR 230.251(a). Neither route is the only option available at this end of the market - private placements under Regulation D and ordinary Form S-1 registrations sit alongside them - but where one of these two applies, it governs how much stock the company may sell, how fast, at what price, and how much disclosure it must publish afterwards. For companies with tiny public floats, the gap between the two is wide enough to change the shape of a capital plan.

Take the shelf route first. Form S-3 is the short-form registration statement that lets an already-reporting company register securities once and sell them in later takedowns. General Instruction I.B.1 makes the form available for primary cash offerings where, in the form's words, "the aggregate market value of the voting and non-voting common equity held by non-affiliates of the registrant is $75 million or more." Companies below that line are not shut out, but they fall into the separate and far narrower path that practitioners call the baby shelf.

That path is General Instruction I.B.6, captioned "Limited Primary Offerings by Certain Other Registrants." Its first condition reads that "the aggregate market value of securities sold by or on behalf of the registrant pursuant to this Instruction I.B.6. during the period of 12 calendar months immediately prior to, and including, the sale is no more than one-third of the aggregate market value of the voting and non-voting common equity held by non-affiliates of the registrant." The SEC's own small-business guide reduces that to a formula: "Amount That Can be Raised = (1/3 x Public Float) - Prior Amounts Sold."

Two further conditions in I.B.6 matter disproportionately at the bottom of the market. The instruction requires that the registrant is not a shell company and has not been a shell company for at least 12 calendar months, and separately that "the registrant has at least one class of common equity securities listed and registered on a national securities exchange." That last clause is decisive: a company quoted over the counter, however small its raise, cannot use the baby shelf. Form S-3's General Instruction I.A.3 adds the timeliness gate, and it has two prongs. Subsection (a) requires that the registrant "has been subject to the requirements of Section 12 or 15(d) of the Exchange Act and has filed all the material required to be filed pursuant to Section 13, 14 or 15(d) for a period of at least twelve calendar months immediately preceding the filing of the registration statement on this Form." Subsection (b) requires that it "has filed in a timely manner all reports required to be filed during the twelve calendar months and any portion of a month immediately preceding the filing of the registration statement," with an express carve-out for reports required solely by an enumerated list of Form 8-K items. A late 10-K or 10-Q therefore breaks eligibility until twelve months of timely filing have passed; a late 8-K under one of the enumerated items does not.

The arithmetic of the one-third cap is worth doing slowly, because it is smaller than it sounds. A listed issuer whose non-affiliate float is worth $24 million may sell $8.0 million of stock under I.B.6 across any rolling twelve calendar months that includes the sale - one third of $24 million. At a $45 million float the allowance is $15.0 million; at a $60 million float, $20.0 million. The one-third test stops binding at the top of the range: Instruction 2 to I.B.6 provides that once the registrant's public float equals or exceeds $75 million, the one-third limitation shall not apply to additional sales, and at that level the registrant qualifies for I.B.1 in any case. The largest allowance the one-third test can therefore ever impose is just under $25 million, one third of a float just under the $75 million line. Instruction 1 tells registrants to compute that float using a price at which the common equity was last sold, or the average of bid and asked prices, as of a date within 60 days prior to the date of sale, so a falling share price shrinks the allowance with a lag.

Now the other ceiling. Rule 251(a) sets Regulation A's two tiers by dollar amount over a twelve-month window. A Tier 1 offering is one in which the sum of the aggregate offering price and aggregate sales "does not exceed $20,000,000, including not more than $6,000,000 offered by all selling securityholders that are affiliates of the issuer." A Tier 2 offering is one in which that sum "does not exceed $75,000,000, including not more than $22,500,000 offered by all selling securityholders that are affiliates of the issuer." Both affiliate sub-limits are exactly 30 percent of their tier ceiling: $6 million against $20 million, and $22.5 million against $75 million. The rule measures aggregate sales to include gross proceeds from securities sold under other offering statements in the twelve months before the current offering begins, and during it.

Rule 251(a) also constrains how much of an offering can be other people's stock. Where an issuer is conducting its first Regulation A offering, or is within one year of it, "the portion of the aggregate offering price attributable to the securities of selling securityholders shall not exceed 30% of the aggregate offering price." That keeps the exemption pointed at primary capital rather than insider exit, at least in the first year.

Set the two ceilings side by side and the spread is stark. The most the one-third test can ever leave available is just under $25 million in twelve months; Tier 2 of Regulation A permits up to $75,000,000 in the same window, three times as much. For a company with an $18 million float, the comparison is $6.0 million against $75 million. That gap is a large part of why Regulation A keeps appearing in the financing plans of companies far too small to interest a bulge-bracket underwriter.

The catch is in Rule 251(d)(3), and it is a large one. Regulation A permits continuous or delayed offerings only in enumerated circumstances, and the rule states plainly that "at the market offerings, by or on behalf of the issuer or otherwise, are not permitted under this Regulation A," defining an at-the-market offering as one made into an existing trading market for outstanding shares of the same class at other than a fixed price. A registered baby shelf can be drawn down through an at-the-market program that dribbles stock into the tape day by day; a Regulation A offering cannot. The issuer trades a higher dollar ceiling for the loss of the most flexible sales mechanic available to small listed companies.

Eligibility under Rule 251(b) excludes a long list of issuers that are common at the nano-cap end. The SEC's compliance guide states that "Regulation A is available only to companies organized in and with their principal place of business in the United States or Canada," which alone disqualifies a substantial share of the foreign-domiciled issuers listed on US exchanges. Rule 251(b) further excludes investment companies and business development companies registered or required to register under the Investment Company Act; development stage companies with no specific business plan or whose plan is to merge with an unidentified company; issuers of fractional undivided interests in oil, gas or other mineral rights; issuers subject to a Commission order of the kind specified in the rule entered in the five years before the offering statement is filed; issuers delinquent in their reporting under Rule 257 or Sections 13 or 15(d) of the Exchange Act; and persons disqualified under the bad-actor provisions of Rule 262.

A 2018 amendment matters for listed issuers specifically. On December 19, 2018 the Commission amended the eligibility provisions under the Economic Growth, Regulatory Relief, and Consumer Protection Act to allow companies subject to the ongoing reporting requirements of Section 13 or 15(d) of the Exchange Act to use Regulation A. The SEC's small entity compliance guide states that "a Tier 2 issuer that is an Exchange Act reporting company is deemed to have met its periodic and current reporting requirements under Regulation A if the issuer meets the reporting requirements of Section 13 or 15(d) of the Exchange Act." A Nasdaq- or NYSE American-listed company using Tier 2 therefore does not stack a second reporting regime on top of its 10-K and 10-Q obligations. Non-reporting Tier 2 issuers do carry that regime: Rule 257 requires an annual report on Form 1-K, a semiannual report on Form 1-SA and current reports on Form 1-U, each within the period specified in the relevant form. The SEC's issuer guidance states those periods as within 120 calendar days of the issuer's fiscal year end for the 1-K, within 90 calendar days after the end of the first six months for the 1-SA, and within four business days of the occurrence for the 1-U. Tier 1 issuers file no ongoing reports, only an exit report on Form 1-Z "not later than 30 calendar days after the termination or completion of the offering."

Two other differences track the tier line. The SEC's guidance states that while Tier 2 issuers must qualify their offerings with the Commission before sales can be made, "they are not required to register or qualify their offerings with state securities regulators" - a preemption Tier 1 issuers do not get, leaving state qualification as a real cost for a small company selling into many states. And the Tier 2 investment limit that caps a non-accredited individual purchaser at 10 percent of the greater of annual income or net worth applies, per Rule 251(d)(2), only in the case of a Tier 2 offering of securities that are not listed on a national securities exchange upon qualification. A listed issuer's Tier 2 offering carries no such per-investor cap.

How much money has moved through the exemption is measurable, but the SEC attaches a caution to its own figures that changes how they should be read. The Commission's Regulation A offering statistics, last updated March 17, 2026 and covering June 19, 2015 through December 31, 2025, report 1,531 qualified offerings across both tiers, an aggregate dollar amount sought of $31,668 million, and 868 issuers reporting proceeds totalling $10,463 million. Those last two figures are not two halves of one ratio. The amount sought is measured across all 1,531 qualified offerings; the reported proceeds come only from the 868 issuers that have filed proceeds information. The Commission states on the same page that "estimates represent a lower bound on the amounts raised, given the time frames for reporting proceeds following completed or terminated offerings and that offerings qualified during the report period may be ongoing." Dividing one number by the other would produce a completion rate the dataset does not support, so this article does not.

A Division of Economic and Risk Analysis white paper published in May 2025, "Analysis of the Regulation A Market: A Decade of Regulation A" by Angela Huang, breaks the earlier decade down further and states its averages directly rather than leaving them to be derived. Over June 19, 2015 through December 31, 2024 it counts 1,426 qualified offerings by 1,197 issuers, of which 1,153 were Tier 2 and 273 were Tier 1 - Tier 2 accounting for just over 80 percent of the count. The paper puts the average amount sought at $19.8 million and the median at $10.0 million; on the proceeds side it reports an average raised of $11.5 million and a median of $2.3 million. The two medians describe different populations - every qualified offering on one side, only issuers that reported proceeds on the other - but the distance between a $10.0 million median target and a $2.3 million median reported outcome is worth holding in mind when reading a nano cap's announced Regulation A plans.

For listed micro caps the financing question is usually entangled with a listing question. Nasdaq's Continued Listing Guide dated August 2026 sets out the Capital Market's three alternative standards: $2.5 million in stockholders' equity under Listing Rule 5550(b)(1), $35 million in market value of listed securities under Rule 5550(b)(2), or $500,000 in net income from continuing operations in the latest fiscal year or in two of the last three fiscal years under Rule 5550(b)(3). Equity raised under either federal route can lift stockholders' equity toward the 5550(b)(1) line; the same issuance enlarges the share count and, where the stock is sold below the prevailing price, transfers value away from existing holders. Neither effect is theoretical at these market capitalisations.

A separate exchange-level constraint sits on top of the federal arithmetic. Nasdaq Listing Rule 5635(d) conditions certain discounted issuances on a shareholder vote; it does not prohibit them. In the text Nasdaq filed with the SEC on January 30, 2018 as SR-NASDAQ-2018-008, shareholder approval is required in connection with a transaction "other than a public offering" where the sale, issuance or potential issuance of common stock at a price less than a defined "Minimum Price" "alone or together with sales by officers, directors or Substantial Shareholders of the Company, equals 20% or more of the common stock or 20% or more of the voting power outstanding before the issuance." That filing defines Minimum Price as "the lower of: (i) the closing price (as reflected on Nasdaq.com); or (ii) the average closing price of the common stock (as reflected on Nasdaq.com) for the five trading days immediately preceding the signing" of the binding agreement. Two qualifications follow. The public-offering carve-out means the test does not reach every discounted deal. And a rule filing from January 2018 is not the live rulebook; anyone testing a specific transaction should read the current Nasdaq rule text. This article applies the rule to no particular financing.

The risks in this corner of the market are structural rather than incidental. Micro- and nano-cap shares frequently trade on thin volume with wide bid-ask spreads, so a financing that is small in dollar terms can be large relative to a day's turnover. Every route described here is dilutive by design. Issuers small enough to be capped by I.B.6 or drawn to Regulation A are disproportionately likely to carry going-concern qualifications in their audited financial statements, and companies below Nasdaq's continued-listing standards face delisting if a deficiency is not cured within the applicable compliance period. Regulation A securities are not restricted securities, but as the SEC's investor bulletin on the exemption warns, "even though there is no resale restriction, you may need to hold your investment for an indefinite period of time" where no liquid market exists.

The practical reading exercise, for anyone tracking a specific company, is short. Check the cover page of any prospectus supplement for the I.B.6 calculation the registrant is required to disclose, which states the float used and the amount already sold in the trailing twelve months. Check whether a Form 1-A has been filed and at which tier. Check the issuer's principal place of business against the United States-or-Canada eligibility condition. And check the twelve-month window, because both ceilings are rolling, and both reset on a calendar the company does not control. Nothing here is a recommendation to buy or sell any security.