A rising stock market has boosted KKR's boom-era buyout fund to a new level of profitability, KKR said Thursday, as it reported first-quarter results that topped Wall Street expectations.

That milestone for KKR's $17.6bn fund, which fueled some of history's biggest leveraged buyouts, combined with a new dividend policy that KKR announced Thursday, helped push the firm's shares to an all-time high.