Aspen Insurance Holdings Ltd. on Tuesday said it has agreed to be bought by private equity firm Apollo Funds in an all-cash deal valued at $2.6 billion, those companies said in a joint statement. Under terms of the agreement, which has been approved by Aspen's board, Apollo will acquire all outstanding shares of the global insurer and reinsurer for $42.75 per share in cash. The transaction is expected to close in the first half of 2019, subject to approval by regulators and Aspen shareholders.