June 7 (Reuters) - Shares of Waystar fell 2.3% below their initial public offering price in their Nasdaq Global Select Market debut on Friday, giving the healthcare payments company a valuation of $3.50 billion.

The company's stock opened at $21, slightly below the IPO price of $21.50, which was at the mid-point of its targeted range of $20 and $23.

Waystar, backed by Swedish private equity firm EQT AB and Canadian pension fund giant CPPIB, raised $967.5 million by selling 45 million shares.

The underwhelming debut bucks the trend in the U.S. IPO market, where stock prices of newly listed companies have surged on the first day of trading.

It also underscores that investors continue to be selective despite the unbridled optimism fueled by some high-profile IPOs.

The Waystar IPO was underwritten by a syndicate of 10 banks including Goldman Sachs, J.P. Morgan Securities and Barclays Capital.

(Reporting by Arasu Kannagi Basil in Bengaluru; Editing by Krishna Chandra Eluri)