Two forms, and the one that changed in 2020 and 2021. The original form, which Nasdaq's Listing Rule IM-5315-1 calls a Selling Shareholder Direct Listing and the NYSE calls a Selling Shareholder Direct Floor Listing, lists a company "at the time of effectiveness of a registration statement filed solely for the purpose of allowing existing shareholders to sell their shares." The company raises nothing; it simply becomes public and its founders, employees and early investors gain a market to sell into. The newer form, Nasdaq's Direct Listing with a Capital Raise under IM-5315-2 (approved by the SEC in May 2021) and the NYSE's Primary Direct Floor Listing (approved in December 2020), lets the company "itself ... sell shares in the opening auction on the first day of trading," either alone or alongside selling shareholders. That second form is what made a direct listing a genuine alternative to an IPO for a company that needs money, not only for one that needs liquidity for its holders.
How an exchange qualifies a company that has no offering price. Listing standards are written around market value, and an IPO supplies one: the offering price times the shares. A direct listing has to substitute. For a selling-shareholder listing on the Nasdaq Global Select Market, the exchange measures the company's Market Value of Unrestricted Publicly Held Shares by "the lesser of" an independent third-party valuation and "the most recent trading price for the company's common stock in a Private Placement Market where there has been sustained recent trading"; if there has been no such trading, the company must provide a valuation showing at least $250 million of publicly held shares. The NYSE's rule works the same way against its $100 million aggregate market value requirement, with the same $250 million valuation-only alternative and a rule of thumb that it will rely on a private-market price only if it reflects a sustained history over several months. For a capital-raise listing on Nasdaq, the exchange counts the company's existing unrestricted shares plus the shares it will sell in the auction, priced at "the lowest price of the price range disclosed by the issuer in its effective registration statement," and requires the total to reach $110 million, or $100 million if the company has at least $110 million of stockholders' equity. Unrestricted matters: shares subject to a lockup agreement, acquired in private placements or otherwise restricted from resale do not count.
The first-day auction and the price range. With no underwriter to set a price, the exchange's opening auction does it. Nasdaq's rule for a capital raise requires that before the stock is released for trading, the company's order to sell its shares and all other market orders be fully executed, and that "the actual price calculated by the cross must be at or above the lowest price and at or below the highest price of the price range established by the issuer in its effective registration statement." If either condition fails, Nasdaq, in consultation with the company's financial advisor, postpones and reschedules the offering rather than open at a price outside the disclosed range. The NYSE's version originally tied its auction to the registration statement's range in the same way and was amended in 2022 to allow the auction to price within limits set below and above that range; the exact limits are in the exchange's current rule text and are not repeated here. The point for an investor is that the range in the prospectus is a constraint on the opening, not a promise of value, and the price the auction produces is the first market price the shares have ever had.
What is different for a buyer. In an IPO the shares sold at the offering price go to investors the underwriters select, and most public buyers acquire shares in the aftermarket at whatever the opening trade sets. In a direct listing there is no allocated tranche: every buyer participates in the same opening auction through their broker, and pays the same auction price. There is also no underwriter stabilizing the price or, in a selling-shareholder listing, any reason for a lockup of the IPO kind, since letting existing holders sell is the purpose of the listing. Supply on the first day is whatever the holders choose to offer, which can be far larger or smaller than an IPO's fixed offering, and that uncertainty is the price of skipping the underwriter. The company, for its part, avoids the underwriting discount and the first-day pricing gap that an IPO's negotiated price can leave on the table, but gives up the underwriters' distribution and their support of the early market.