One of last year's top-performing hedge fund managers, Deepak Narula, is suffering a reversal of fortune as the mortgage bonds that steered him to the top of the industry in 2012 are now delivering losses.

His Metacapital Management's roughly $1.5 billion flagship fund was down 5.66 percent for the year through June 14, according to an investor with knowledge of the numbers.

The loss is particularly given the fund's 41 percent gain last year.

Narula's fund is just one of many credit-oriented hedge funds that have seen gains posted earlier this year turn into losses in the wake of a ferocious sell-off in bonds sparked by fears the Federal Reserve could pull back from its easy money policies later this year.

Other large hedge funds with significant credit exposure that are posting negative numbers since Fed Chairman Ben Bernanke signaled a potential end to the monthly purchases of $85 billion in Treasuries and mortgage securities include Brevan Howard, Bridgewater Associates and BlueCrest Capital Management.

Metacapital, for instance, tumbled into the red after the fund lost 7.26 percent in May alone, according to the investor familiar with the numbers.

Two other sources familiar with Metacapital said the fund has lost more ground in recent weeks as the value of mortgage-backed securities has continued to fall. Those sources did not have more recent performance figures.

Narula did not return a request for comment.

Funds like Metacapital benefited mightily last year from the Fed's decision in September to begin buying Treasuries and agency mortgage-backed securities in order to keep interest rates low. The bond buying drove investors into riskier, higher-yielding assets, as well giving a jolt to the prices of more traditional bonds.

Bonds backed by subprime mortgages performed especially well along with mortgage securities issued by Fannie Mae and Freddie Mac. Last year, Metacapital was an investor in both kinds of mortgage securities.

But as concerns rose in May that the Fed would begin to taper its bond purchases, the yields on Treasuries and agency mortgage securities have soared as the prices of bonds have fallen. The sudden drop in bond prices has caught some managers flat-footed.

Funds that make relative value mortgage trades using leverage will likely be some of the hardest hit investors this month, said several people in the hedge fund community, including allocators and traders.

Smaller hedge funds are not the only ones that have been caught in the market crossfire.

BlueCrest Capital's $13.6 billion Bluetrend fund, which invests in interest rates, currencies and stocks, lost 7 percent in May, said two people familiar with the fund's performance. For the year through June 14, the fund was down 3.7 percent, according to a person familiar with the numbers.

A representative for the fund had no comment.

Two of the world's biggest hedge funds, Bridgewater and Brevan Howard, have each rung up significant losses in the past few weeks.

The $70 billion Bridgewater All Weather fund lost about 6 percent through this month, pushing yearly losses to about 8 percent, Reuters reported on Monday. Another Bridgewater portfolio, the Pure Alpha II fund, was down 1.12 percent for the year as of June 18, said a person familiar with the numbers.

A $2.7 billion Brevan Howard fund that focuses on emerging markets had fallen 11.6 percent to June 14, Reuters reported last week.

(Reporting By Katya Wachtel and Jennifer Ablan; editing by Matthew Goldstein and Leslie Adler)