BlackRock Inc. will acquire private capital database provider Preqin for £2.55 billion ($3.2 billion) in cash, as the world’s largest money manager accelerates its push to become a major player in alternative assets.The acquisition deepens BlackRock’s ability to oversee risks and analyze data across fast-growing markets for private assets, and also expands its Aladdin technology systems, the New York-based firm said in a statement on Sunday....