The world's largest bond manager is surprisingly absent from the Standard & Poor's Capital IQ list of top-rated investment funds for the last 10 years.

S&P Capital IQ monitors the fund ratings of investment banks and wealth managers worldwide. Last month, the firm announced it would list the top performers, ratings wise.

Qualifying funds must have remained within the Platinum, Gold or Silver gradings (formerly AAA, AA and A fund ratings) over the 10-year period.

As expected fund programs run by BlackRock, Bank of New York Mellon, Henderson and Invesco all made the list.

However, mega-investor PIMCO did not. One potential explanation is the PIMCO total Return Fund exposure to Treasurys and U.S. mortgages. Neither are very popular with the other fund managers.

PIMCO may manage the largest bond investment platform on the planet, but from the S&P perspective, bigger isn't better.

More on the fund list here.