SEC Rule 101 of Regulation M

Overview and Regulatory Purpose

The relationship between a distribution participant and the market for the security it is distributing creates a structural conflict of interest of significant potential for market harm. 

An underwriter selling shares in a public offering at a specified offering price has a direct financial interest in preventing the market price of the security from falling below the offering price during the distribution period — a price decline that would make the offering economics unfavourable for investors and potentially cause the offering to fail. 

If underwriters were permitted to make open-market purchases of the security during the distribution period, they could use those purchases to prevent the price decline that genuine market forces would otherwise produce, artificially supporting the offering price and misleading investors about the true market value of the security being sold to them.

Rule 101 prevents this market distortion by establishing a restricted period during which distribution participants and their affiliated purchasers may not bid for, purchase, or attempt to induce purchases of the subject security. 

By removing the distribution participant from the buy side of the market during the critical period leading up to and through the pricing of the offering, the rule allows the market price of the security to reflect genuine supply and demand rather than the artificial support of the very parties seeking to distribute shares at that price. 

The result is a more accurate price discovery process that serves the interests of both issuing companies — whose securities are priced at levels reflecting genuine market demand — and investors — who receive securities at prices that represent an undistorted assessment of value rather than prices inflated by the underwriters' own purchasing activity.

Statutory Authority and Rulemaking History

Rule 101 derives its statutory authority from Sections 9(a)(2) and 10(b) of the Securities Exchange Act of 1934 — which prohibit manipulation of securities prices — and from Section 17(a) of the Securities Act of 1933, which prohibits fraud and deception in the offer or sale of securities. These provisions collectively authorise the Commission to prescribe means reasonably designed to prevent manipulative conduct in connection with securities distributions.

Regulation M was adopted January 3, 1997 — Securities Exchange Act Release No. 34-38067, published at 62 FR 544 — replacing the prior manipulation rules governing securities offerings, most significantly Rule 10b-6, which had governed underwriter market activities during distributions since 1955. The 1997 rulemaking substantially modernised the offering manipulation framework, introducing the ADTV-based approach to determining the scope of restrictions, the actively-traded securities exception that eliminates the restricted period for the most liquid securities, and the differentiated restricted period structure based on the liquidity characteristics of the security being distributed.

Rule 101 was most recently amended June 20, 2023 — 88 FR 39994 — in the Commission's rulemaking removing references to credit ratings from Regulation M. That amendment replaced the prior investment-grade exception — which had permitted distribution participants to purchase investment-grade non-convertible debt and preferred securities during the restricted period based on credit rating agency classifications — with a new Credit Risk Exception based on probability of default analysis, in response to the Dodd-Frank Act's directive to remove reliance on credit ratings from Commission rules.

Key Provisions and Operative Requirements

Rule 101(a) establishes the core prohibition. In connection with a distribution of securities, it is unlawful for a distribution participant or any affiliated purchaser of a distribution participant, directly or indirectly, to bid for, purchase, or attempt to induce any person to bid for or purchase a covered security during the applicable restricted period. The prohibition covers the covered security — the security being distributed — and, through Rule 100's definition of reference security, any security into which the subject security is convertible, exchangeable, or exercisable, or which under the terms of the subject security may in whole or significant part determine its value.

The restricted period — the period during which Rule 101's prohibition applies — is determined by the trading characteristics of the security being distributed. For securities with an ADTV value of $100,000 or more and issuers with a public float of $25 million or more, the restricted period begins one business day before the pricing of the offered security and ends upon the completion of the distribution participant's participation in the distribution. For securities with an ADTV value of less than $100,000 or with issuers having a public float of less than $25 million, the restricted period begins five business days before pricing and ends upon completion. The ADTV-based differentiation reflects the Commission's recognition that the risk of manipulation is inversely correlated with a security's liquidity — actively traded securities with large public floats are more resistant to price manipulation because the market's depth and breadth makes artificial price support difficult to sustain, while illiquid securities are more susceptible.

Rule 101(c)(1) provides the actively-traded securities exception — one of the most commercially significant provisions in the rule. Distribution participants are entirely exempted from the Rule 101 prohibition for covered securities that have an ADTV value of at least $1 million and issuers with a public float of at least $150 million. For these actively-traded securities, no restricted period applies and distribution participants may freely bid for and purchase the covered security during the distribution without restriction under Rule 101. This exception reflects the Commission's determination that securities with sufficiently high trading volume and issuer public float are effectively immune from manipulation through distribution participant purchasing activity — the market's depth is sufficient to absorb any attempt at artificial price support without producing a meaningful distortion.

Rule 101(b)(7) provides the de minimis exception — permitting distribution participants and their affiliated purchasers to make purchases during the restricted period that do not exceed 2% of the ADTV of the security during any single trading day, provided the purchases are not made through the distribution and are not made to facilitate the distribution. This narrow exception acknowledges that very small purchases relative to overall market volume cannot meaningfully affect the market price and should not be prohibited simply because the purchaser is a distribution participant.

Rule 101(c)(4) — the Credit Risk Exception adopted by the June 2023 amendment — provides an exception for purchases of investment-grade non-convertible debt, asset-backed securities meeting specified conditions, and non-convertible preferred securities with ADTV values of at least $1 million during the restricted period, where the purchasing distribution participant receives from the lead manager or managing underwriter a probability of default analysis covering the issuer and the offered security. This exception replaced the prior investment-grade credit rating exception, implementing the Dodd-Frank Act's mandate to remove reliance on credit ratings by replacing the rating-based standard with a substantive creditworthiness analysis requirement.

Rule 101(c) also provides several additional specific exceptions permitting certain categories of purchase that do not present the manipulation risks the rule is designed to prevent: odd-lot transactions, exercises of securities, unsolicited purchases pursuant to published buying programs, purchases as part of a plan of distribution under an effective registration statement, stabilising transactions permitted by Rule 104, and transactions by certain affiliated purchasers that are market makers in the security, subject to specified conditions limiting the volume and manner of those market-making activities.

Scope of Application

Rule 101 applies to every distribution participant and every affiliated purchaser of a distribution participant during every distribution of securities — whether registered or unregistered, whether conducted by the issuer or by selling securityholders, and whether the distribution participant is the managing underwriter, a syndicate member, a broker-dealer in the selling group, or any other person who has agreed to participate or is participating in the distribution. The Rule 100 definition of distribution participant — any underwriter, prospective underwriter, broker, dealer, or other person who has agreed to participate or is participating in a distribution — is deliberately broad, capturing every entity in the distribution chain that has any ongoing financial interest in the outcome of the offering.

The affiliated purchaser concept — defined in Rule 100 to encompass entities controlling, controlled by, or under common control with the distribution participant, as well as any person acting in concert with the distribution participant to acquire covered securities — prevents distribution participants from circumventing the rule by routing prohibited purchases through affiliated entities rather than making them directly.

Relationship to Related Rules and Regulations

Rule 101's prohibition on distribution participant market activity is the companion provision to Rule 102's parallel prohibition on issuer and selling securityholder market activity. Together Rules 101 and 102 cover all categories of person with a significant interest in the outcome of a securities distribution — Rule 101 covers the underwriters and other distribution intermediaries, and Rule 102 covers the principals on whose behalf the distribution is conducted. The two rules share a common definitional framework through Rule 100's definitions and common exceptions structure, creating a unified anti-manipulation regime for the full spectrum of offering participants.

Rule 104 — the stabilisation rule — defines the only category of market activity by distribution participants that is expressly permitted notwithstanding Rule 101's general prohibition. A managing underwriter may conduct stabilising bids and purchases in the security being distributed, provided those activities comply with Rule 104's specific conditions governing the price at which stabilising bids may be entered, the disclosure requirements applicable to stabilising activity, and the mechanics of syndicate covering transactions and penalty bids. Rule 104's stabilising activity permission is the safety valve that allows underwriters to manage post-pricing price volatility through limited and disclosed market activity without violating Rule 101's broader prohibition.

Rule 105 — the short selling anti-manipulation rule — operates alongside Rule 101 by prohibiting the purchase of a security in a registered public offering from an underwriter, broker, or dealer participating in the offering within five business days before pricing, where the purchaser has effected a short sale in that security. Rule 105 addresses a specific manipulation technique — short selling in advance of an offering to profit from the distribution's typical downward price pressure — that Rule 101 does not directly target.

Amendment History and Regulatory Evolution

Rule 101's fundamental architecture has been stable since Regulation M's adoption in 1997, with the ADTV-based restricted period structure, the actively-traded securities exception, and the de minimis provision remaining unchanged in their core elements. The 2023 amendment's replacement of the investment-grade credit rating exception with the Credit Risk Exception based on probability of default analysis was the most consequential change to Rule 101's operative provisions since the rule's original adoption, reflecting both the Dodd-Frank mandate and the Commission's determination that the credit rating agency exception had become embedded in market practice in ways that warranted a more substantive creditworthiness standard.

The broader Regulation M reform agenda that the Commission announced in December 2023 — proposing amendments to Rules 101 and 102 to address new transaction structures, the growth of block trading, and the market microstructure changes since 1997 — remained pending through June 2026 without formal adoption of proposed rule text. The proposal indicated a potential tightening of the exceptions available to certain categories of distribution participant and a reassessment of the actively-traded securities exception's thresholds.

Enforcement Context and SEC Action Patterns

Rule 101 enforcement has focused on two categories of violation. The first involves distribution participants that made unauthorised purchases of covered securities during the restricted period without qualifying for any applicable exception — most commonly managing underwriters whose market-making desks purchased shares of a security that was simultaneously being distributed in an offering in which the firm was acting as underwriter, in violation of the prohibition on purchasing during the restricted period. These violations frequently reflect deficiencies in the firm's information barrier procedures that were designed to prevent market-making and underwriting personnel from trading on the same side of the market in the same security simultaneously.

The second category involves the misuse of exceptions — particularly the actively-traded securities exception — through the mis-categorisation of securities that do not genuinely meet the ADTV and public float thresholds as actively-traded. The Commission has emphasised that the exceptions to Rule 101 are conditioned on objective quantitative thresholds and that distribution participants cannot rely on estimates or approximations that do not accurately reflect the security's actual trading characteristics.

Examination Relevance and Key Takeaways

Rule 101 is examined at the Series 7 and Series 65 levels in the context of the registered offering process and the anti-manipulation rules applicable to underwriters. The restricted period concept — one business day before pricing for more liquid securities, five business days for less liquid securities — and the actively-traded securities exception eliminating the restricted period entirely for securities with ADTV of at least $1 million and issuer public float of at least $150 million are the primary examination concepts. The de minimis exception permitting purchases not exceeding 2% of ADTV on any single day is examined as the narrow accommodation for very small purchases that do not present manipulation risk.

The key points to retain are these. Rule 101 of Regulation M prohibits distribution participants and their affiliated purchasers from bidding for or purchasing a covered security during the restricted period — one business day before pricing for securities with ADTV of $100,000 or more and issuer public float of $25 million or more, five business days for less liquid securities. The actively-traded securities exception eliminates the restricted period for securities with ADTV of at least $1 million and issuer public float of at least $150 million. 

The de minimis exception permits purchases not exceeding 2% of ADTV per day. The Credit Risk Exception, adopted in June 2023, permits purchases of qualifying investment-grade non-convertible debt, ABS, and preferred securities based on probability of default analysis, replacing the prior credit rating exception. Stabilising transactions compliant with Rule 104 are expressly permitted notwithstanding the general prohibition. Rule 101 applies to the full range of distribution participants from managing underwriters through selling group broker-dealers and their affiliated purchasers. Rule 101 was last amended June 20, 2023 and no formal rulemaking has been adopted to amend the rule through June 2026.