Quintiles, the Triangle-based international biopharmaceutical giant, was named Monday to the Fortune 500 list of largest U.S. companies ranked by revenue.

“Being named to the Fortune 500 is a significant milestone in Quintiles’ history,” CEO Tom Pike said in a statement.

Last month, the company marked a year since its most recent public offering, one described by veteran financial observers as the largest ever IPO by a Triangle firm.

Co-founder Dennis Gillings took the company private, citing freedom from the scrutiny given public companies as one of the major reasons for the decision. When Gillings moved into a less active role and Pike took over as CEO, he led the company back toward the trading floor.

“We operated as a private company for a full decade before returning to the public markets via IPO in 2013. Our inclusion in the Fortune 500 is another indicator that Quintiles is one of the most important companies headquartered in the United States,” Pike said.

Shares in the company, which trades on the New York Stock Exchange under the ticker symbol “Q,” were at $50.97 Monday morning. The company employs about 29,000 people and has operations in 100 countries.