The forced purchase of a security when there are insufficient buyers. Eating stock often applies to underwriters of an initial public offering (IPO), if a certain level of subscription is guaranteed but is not met. This allows the company going public to have a better approximation for the amount of capital it will raise from the offering.
Underwriters mitigate the risk associated with eating stock, in IPOs that it offers, by charging a substantial underwriting fee. Eating stock does not mean that the underwriter will take a loss on the entire venture, as the underwriting fee may exceed the cost of shares that it was forced to absorb.