(Bloomberg) -- Pinegrove Opportunity Partners has raised $2.2 billion for its debut fund, closing a large investment round in a fast-growing niche of the venture capital market. The San Francisco-based firm is what’s known as a venture secondary. It buys existing ownership stakes in other venture-backed companies or funds rather than leading primary rounds that may fund a company’s future growth. The venture secondaries market has been growing and attracting interest as the traditional venture capital model ...