NEW YORK (AP) — With Bill Gross’ surprise departure from Pimco, 45-year-old Daniel Ivascyn now finds himself watching over trillions in assets at the huge mutual fund firm.

The new chief investment officer takes over from a fiery Wall Street legend. Gross co-founded Pimco in 1971 and ran the firm for four decades, turning the company’s flagship product, the Total Return Fund, into a $221 billion behemoth. His success earned him the title “Bond King.”