Meaning
Potential dilution resulting from the pool of unexercised options and convertible instruments limits the future returns of current shareholders. An equity overhang measures the size of these future claims against the total capitalization of the firm. It applies as long as there are outstanding grants or reserved pools that have not yet converted into common stock.
Valuation Drag
Market participants view a large pool of promised shares as a future cost that reduces the price of each current share. An equity overhang indicates that a portion of any future growth will be captured by option holders rather than current owners. This reality makes it harder for a founder to raise money at a high valuation.
Issuance Limit
Boards of directors monitor the ratio of reserved shares to ensure the company can still attract new talent without upsetting current investors. An equity overhang that exceeds fifteen percent often requires a formal review.
Investor Caution
Professional funds look at the total possible share count when calculating their potential return on investment. If the equity overhang is too large, the fund might demand that the founders cancel some of the unallocated pool before the investment goes through. This process ensures that the new investors do not take an immediate loss on their ownership percentage.
It forces the founding team to be careful with how many options they grant in the early days. A high percentage of promised but unissued shares can signal poor capital management to the market.