The general rule (as set forth in Rule 413(a) under the Securities Act) is that a company cannot register additional securities on a registration statement that is already in effect; instead, a company must file a new registration statement to register any additional securities—even when the additional securities are of the same class as those already registered. While this is always the case for a registration statement on Form S-8, there are fortunately some exceptions for a registration statement on Form S-3. The exceptions, however, require that you start with an automatic shelf registration statement. Thus, using a post-effective amendment to register additional securities only becomes possible for a public company that qualifies as a “well-known seasoned issuer” or “WKSI” (a category of issuer established in 2005 under the SEC’s Securities Offering Reform (SEC Release No. 33-8591) for the most widely followed public companies in the U.S. marketplace).

A WKSI enjoys special benefits due to its issuer status—in particular, it is eligible to register certain offerings of securities on a Form S-3 registration statement that will be automatically effective upon filing with the SEC. If an issuer does not qualify for WKSI status, it is not eligible to file an automatic shelf registration statement. Pursuant to Rule 413(a), this would preclude it from registering additional securities of any class on a post-effective amendment. Further, even if an issuer does qualify for WKSI status as of the most recent eligibility determination date, it cannot amend an already effective shelf to convert it into an automatic shelf.

If a WKSI does have an automatic shelf in effect, it can utilize the exception in Rule 413(b) to register additional securities (or additional classes of securities) by filing a post-effective amendment to the automatic shelf, but only if the new securities are either (1) of a different class than those already registered on the automatic shelf or (2) of a majority-owned subsidiary and permitted to be included in an automatic shelf.

Although WKSIs have more flexibility than other categories of issuers and are not required to specify a maximum aggregate offering price or number of shares in the base prospectus of an automatic shelf, they may choose to do so. However, Rule 413(b) noticeably omits any reference to adding securities of the same class as those already registered.

This begs the question— if a WKSI has specified a number of shares in the base prospectus, can it use a post-effective amendment to register additional securities of the same class as those already registered on its automatic shelf? The SEC Staff eventually addressed this very question in question 210.03 of the Compliance and Disclosure Interpretations on the Securities Act Rules. The Staff confirmed that the answer is yes, “an issuer may add to the automatic shelf registration statement on Form S-3, by post-effective amendment, more securities of the same class already registered.” A couple of examples include a post-effective amendment to an automatic shelf filed by Tesla, Inc. (formerly known as Tesla Motors, Inc.) on September 28, 2012 and, more recently, a post-effective amendment to an automatic shelf filed by Delta Air Lines, Inc. on March 30, 2017. Pursuant to Rule 462(e) under the Securities Act, just like the automatic shelf itself, a post-effective amendment to an automatic shelf would automatically become effective upon filing with the SEC.

If an issuer cannot utilize Rule 413(b) (because it either does not qualify as a WKSI or the applicable registration statement is not an automatic shelf) and must file a new registration statement to register additional securities, there may still be some welcome relief available under Rule 462(b) under the Securities Act. The timeframe for its utilization is limited, however, and thus it is not the functional equivalent of the Rule 413(b) exception.

Rule 462(b) provides for immediate effectiveness, upon filing with the SEC for a new registration statement, if (1) the new registration statement registers additional securities of the same class as were included in an earlier registration statement for the same offering and was declared effective by the SEC, (2) the new registration statement is filed prior to the time confirmations are sent or given, and (3) the new registration statement registers additional securities in an amount and at a price that together represent no more than 20% of the maximum aggregate offering price included in the earlier registration statement. Thus, Rule 462(b) allows a non-WKSI to react quickly and upsize an offering by up to 20% if desired.

Another benefit of Rule 462(b) is that an issuer utilizing the rule can file a short-form registration statement. As set forth in General Instruction IV.A to Form S-3, a new registration statement filed pursuant to Rule 462(b) may consist of only (1) the facing page, (2) a statement that the contents of the earlier registration statement, identified by file number, are incorporated by reference, (3) required opinions and consents, (4) the signature page, and (5) any price-related information omitted from the earlier registration statement pursuant to Rule 430A that the registrant decides to include in the new registration statement.

Accordingly, while only WKSIs can register additional securities by post-effective amendment to an automatic shelf, non-WKSIs may still be able to take advantage of Rule 462(b) to expeditiously register additional securities in certain circumstances.