Morgan Stanley Wealth Management has launched its Private Markets Transaction Desk, a “concierge service” that enables certain clients to buy and sell qualified private company shares in the “highly fragmented and opaque secondary market,” according to the firm.

The demand for liquidity solutions grows when companies remain private for longer, the firm said. The service will provide accredited investors with access to stakes in Morgan Stanley’s portfolio of firms, wealth management clients, and institutional investors.

Growth-stage venture-backed global companies worth over $1 billion have grown from 150 in 2015 to more than 1,000 today, with a current cumulative valuation of $4.3 trillion, the firm noted.

“Alternative investments like private market shares are only growing in importance as investors seek deeper portfolio diversification,” said Jed Finn, head of Morgan Stanley Wealth Management.

Morgan Stanley is pushing the new service, that adds to existing private investment platforms it already provides to wealth management clients, as a method for private firm shareholders to receive direct support for one-off stake sales.

Jeff Urban was tapped to lead the desk. He has led several leading private and public markets distribution and syndication businesses, Morgan Stanley said.