Rule 105 restricted period

The Rule 105 restricted period is the shorter of two windows ending at the pricing of an offering: the five business days before pricing, or the time from the first filing of the registration statement to pricing. A short sale inside it bars the seller from buying in that offering, unless an exception applies.

manipulation techniques · updated 2026-09-20

Where does rule 105 restricted period come up?

This term is used in the following manipulation techniques, each explained in full on its own page.

• Rule 105 offering shorts — Rule 105 offering shorts are short sales of a stock in the restricted period before a follow-on offering is priced, followed by a purchase of that stock in the offering, which Regulation M Rule 105 prohibits whatever the trader intended.

Enforcement actions involving these techniques

See also

• Rule 105 — Rule 105 of Regulation M, 17 C.F.R. § 242.105, makes it unlawful to sell a stock short in a defined restricted period before a reg…
• Bona fide purchase exception — The Rule 105 bona fide purchase exception lets a trader who sold short in the restricted period still buy in the offering, if befo…

Terms that refer here

Bona fide purchase exception · Rule 105

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