Mark O'Hare became a billionaire after BlackRock acquired his data company. Now he's turning his employees into millionaires.

• Preqin employees are getting paid after BlackRock acquired the company for $3.2 billion.
• Staffers will share about $650 million, making some of them millionaires.
• Preqin founder Mark O'Hare and his wife will walk away with about $2 billion after taxes.

Some Preqin employees are poised for a big payday after BlackRock acquired the data company for $3.2 billion.

The acquisition, announced on June 30, has made Preqin founder Mark O'Hare and his wife billionaires.