It stands for post-effective amendment; in relation to public offerings (initial public offerings, IPOs), it is an amendment to a registration statement that is not immediately effective upon filing. The amendment becomes effective upon filing with the regulatory authority.

For example, a post-effective amendment may be made to deregister part of the securities offered for some reasons, such as remaining unsold as of the date of the amendment.

It is also abbreviated as POS AM.

PE may also stand for private equity.