Example: A firm with 1 million shares has set aside $4 million in cash to distribute to shareholders via a tender offer. Upon announcing that the cash will be distributed to shareholders, the price per share is $44. Due to personal taxes, the firm decides to pay a premium to entice investors to give up their shares. Suppose the firm pay $6 premium (i.e. $50 per share). Assume you bought the shares for $10/share years ago.

What is the tax rate on capital gains that makes you indifferent between staying (with the firm) vs. selling (the shares back to the firm)?