Preferred stock classification and mezzanine equity

Preferred stock that is redeemable at the holder's option, or upon an event outside the company's control such as a deemed liquidation, is classified as temporary equity, also called mezzanine equity, under the SEC's guidance in ASC 480-10-S99. Most venture financings contain such provisions, so most private biotechs present their preferred stock outside permanent equity even before they are SEC registrants.

If redemption is mandatory on a fixed date, the instrument is a liability under ASC 480. If it is redeemable only on a liquidation, it may be permanent equity. Each series is analyzed on its own terms, and features such as participating dividends, anti-dilution ratchets, and conversion caps are assessed for embedded derivatives under ASC 815.

The classification drives whether the instrument is accreted to redemption value through equity, whether changes in value hit the income statement, and how the stockholders' deficit that most biotechs show is presented. A memo per series at issuance is standard and expected.