Aug 4 (Reuters) - Apollo Global Management Inc (APO.N) said on Wednesday its second-quarter distributable earnings more than doubled thanks to a surge in profits from asset sales in its private equity business and transaction fees from its credit division. The result, which beat estimates, was the first full quarter reported by Apollo with its co-founder Marc Rowan serving as chief executive officer. He replaced Leon Black, who relinquished control of the firm in March following a review of his ties to the late financier and convicted sex offender Jeffrey Epstein. Apollo"s other co-founder, Josh Harris, announced in May that he would leave Apollo by early next year. He has now been removed as a "keyman" in Apollo"s flagship private equity fund, Rowan said during an analyst earnings call. A keyman in a private equity fund is a fund manager whose absence can lead to the suspension of a fund"s investment period. Apollo"s shares were down 1.2% in early afternoon trading in New York at $59.91. New York-based Apollo"s distributable earnings, which represent the cash for paying dividends to shareholders, rose to $501.6 million from $205.2 million posted a year ago. That resulted in distributable earnings per share of $1.14, ahead of a Refinitiv consensus estimate of 71 cents. Apollo said it invested $27.8 billion during the quarter, mostly in its credit and private equity portfolios. It also cashed out investments worth $9 billion, mainly in its holdings of public and private companies. The firm collected about $55 million in transaction fees from its credit unit, which encompasses its Athene franchise. Rivals Blackstone Group Inc (BX.N), Carlyle Group Inc (CG.O) and KKR & Co Inc (KKR.N) have also reported strong second-quarter results, as buoyant public markets and a rebound in economic growth allowed private equity firms to sell investments. Apollo said its private equity funds appreciated by 9.5% during the quarter, while its corporate credit and structured credit funds rose 2% and 4.5% respectively. By comparison, private equity funds managed by Blackstone, Carlyle and KKR grew 12%, 13.8% and 9% respectively. Under generally accepted accounting principles (GAAP), Apollo reported a net income of $648.6 million, up 48% from a year ago driven by a rise in gains from investment activities. Apollo ended the quarter with $471.8 billion in assets under management and $47.6 billion in unspent capital. It raised $12 billion in new capital and declared a quarterly dividend of 50 cents per share, unchanged from the previous quarter.