Final answer:
When a firm authorizes a trustee to repurchase shares as they become available, they are using a stock repurchase or share buyback technique.
Step-by-step explanation:
The firm is using a technique called a stock repurchase or share buyback. In this technique, the firm authorizes a trustee to repurchase its own shares from existing shareholders as they become available. This means that the firm is buying back its own stock from the market, which can help increase the value of the remaining shares and return cash to shareholders.
A stock repurchase, also known as a share buyback or stock buyback, is a corporate action in which a company buys back its own outstanding shares from the open market. Companies engage in stock repurchases for various reasons, and the process involves using the company's cash or borrowing funds to buy back shares from existing shareholders.