The private equity firm, which keeps its books in U.S. dollars, said the profit amounted to $3.22 per share for the quarter ended Sept. 30 compared with a profit of $98 million or $1.50 per share a year ago.
The jump in profit came as Onex recorded a $551 million recovery of income taxes compared with $89 million a year ago.
Revenue for the quarter totalled $7.13 billion, up from $6.14 billion, boosted by acquisitions made last year.
Onex noted that it has a strong financial position as it looks for new acquisitions with $1.5 billion of cash and near-cash equivalents and roughly $1 billion in undrawn committed capital.
The company holds investments in a wide range of companies including a large stake in electronics maker Celestica Inc. (TSX:CLS).