NEW YORK, May 1 (Reuters) - Private equity firm KKR & Co Inc said on Wednesday its first-quarter adjusted net income jumped 20% year-on-year, driven by strong management and transaction fees as well as earnings from its annuities business.

KKR's adjusted net income rose to $863.7 million from $719.3 million a year earlier. That resulted in adjusted net income per share of 97 cents, which was slightly ahead of the average analyst estimate of 96 cents, according to LSEG data.

Fee-related earnings rose 22% to $668.7 million, buoyed by income KKR generates from fees associated with managing $578 billion worth of total assets in addition to transaction fees from arranging financing from its own deals.

KKR's earnings from investing the capital of its annuities business Global Atlantic rose 33% to $273 million. During the quarter, KKR completed the $2.7 billion deal to acquire the remaining 37% stake in Global Atlantic that it doesn't already own.

Dividends from KKR's "strategic holdings", which are mostly private equity investments that it plans to hold for relatively longer periods, reached $20.7 million in the quarter.

KKR's private equity portfolio appreciated by 5%, opportunistic real estate funds gained 1%, and leveraged credit funds added 3%.

By contrast, Blackstone reported that its corporate private equity funds appreciated by 3.4%, liquid credit funds gained 2.5%, and opportunistic real estate funds were flat.

KKR's net income under generally accepted accounting principles more than doubled to $682.2 million, driven by growth in revenues from Global Atlantic.

It raised $31 billion of new capital, invested $14 billion, retained $98 billion of unspent capital, and declared a quarterly dividend of 17.5 cents.

(Reporting by Chibuike Oguh in New York; Editing by Kim Coghill)