In the months before the blowup of Third Avenue’s junk bond fund in early December, investors and financial advisors called the New York-based investment company to voice their concerns about the growing percentage of hard-to-trade, illiquid assets in the fund’s portfolio. “I would call up and they would say, ‘We’re under control, we have plenty of cash,'” said Richard Berse, president of Northstar Financial Advisors Inc in New Jersey.