Vanguard does not wait for “unicorn” startups such as Uber, WeWork, and Airbnb to go public before acquiring their shares, writes Joseph DiStefano for the Philadelphia Inquirer.

A unicorn is a privately held startup company valued at more than $1 billion. Uber’s IPO is scheduled for Friday, May 10.

Vanguard is one of the big investors that acquired preferred shares of these companies in private sales. These investors buy stocks from companies that have not yet gone public and post estimates of their value next to the publicly traded stocks they own.

In a Feb. 28 filing, Vanguard posted valuations for Uber of $43.44 a share, a 24 percent increase over the last year, and WeWork was priced at $68, an increase of 31 percent.

Meanwhile, the S&P 500 rose by just seven percent.

However, Vanguard’s analysis of private companies is not always that optimistic. In the same filing, Airbnb was valued at around $110 a share, trailing the market by four percent.

According to Vanguard spokesperson Emily Farrell, Vanguard has an independent committee that determines the fair-market value of its private investments. In estimating values, the committee considers “financial performance, corporate actions, offering price, market conditions, and guidance from external advisers.”

Read more about Vanguard’s investment in unicorn startups in the Philadelphia Inquirer here.