SeaWorld (SEAS) - Get Report made a splash with investors on Tuesday after announcing that long-time investor Hill Path Capital was raising its stake in the company to 34.5%, and that it is also buying back its own stock from an affiiliate of investment Pacific Alliance Group to the tune of $150 million.

Shares of SeaWorld swelled nearly 18% in mid-day trading on Tuesday to $32.06 after private-equity firm Hill Path Capital said it agreed to acquire 13.2 million shares of SeaWorld from an affiliate of Pacific Alliance Group, boosting its total stake in SeaWorld to 34.5%.

Based on Friday's closing stock price of $27.25, the agreement would add up to $360 million in additional capital for SeaWorld. The agreement also includes appointing up to three Hill Path director nominees to SeaWorld's board.

At the same time, SeaWorld said it has also agreed to buy back an additional 5.6 million of its own shares from a separate affiliate of Pacific Alliance Group for another $150 million.

"We are thrilled that Hill Path has agreed to increase its investment in SeaWorld," SeaWorld CEO Gus Antorcha said in a statement.