Here’s the definitions on investopedia
What Is a Buyback?
A buyback, also known as a
share repurchase, is when a company buys its own outstanding shares to reduce the number of shares available on the open market. Companies buy back shares for a number of reasons, such as to increase the value of remaining shares available by reducing the supply or to prevent other shareholders from taking a
controlling stake.
What Is a Reverse Stock Split?
A reverse stock split is a type of
corporate action that consolidates the number of existing shares of stock into fewer, proportionally more valuable, shares. Reducing the total number of outstanding shares in the open market can be pursued for a number of reasons, and often signals a company in distress.
A reverse stock split divides the existing total quantity of shares by a number such as five or ten, which would then be called a 1-for-5 or 1-for-10 reverse split, respectively. A reverse stock split is also known as a stock consolidation, stock merge or share rollback and is the opposite exercise of a stock split, where a share is divided (split) into multiple parts.