The firm also said it appointed Yi-Lin Lee as senior fixed income strategist and portfolio manager.
Tan and Lee will co-manage the firm’s discretionary fixed income strategy.
Both of their roles are newly-created, according to a spokeswoman.
Thirdrock, which set up as a multi-family office in 2010, is both an asset manager and wealth manager.
"The expansion of our suite of investment products that our clients can access is essential to growing our business," Jason Lai, CEO and founder of the firm, wrote in an emailed answer to FSA. "Apart from our managed accounts, there may be clients who prefer a suite of ready strategies.
"Our fund management platform with its lineup of funds, as well as discretionary portfolio management offerings, will meet that need and offer our clients a more comprehensive array of investment options.”
Before joining Thirdrock, Tan was the lead portfolio manager for China credit and head of Asian private credit for Blackrock, co-managing fixed income portfolios of $8bn.
Tan was also an investment director and head of Southeast Asia at Citi Venture Capital International, the emerging markets private equity arm of Citigroup and a senior member of its China investment team.
Lee previously worked for the fixed income trading businesses of Merrill Lynch, Deutsche Bank, Royal Bank of Scotland and Haitong International with management in the last two roles.
In June, Thirdrock named Eric Goh as investment strategist and senior client adviser.