Pacific Investment Management Co.’s Bill Gross said the Federal Reserve will likely shift focus to mortgage securities to keep borrowing rates low when its so-called Operation Twist program ends in June.

It will be a “twist on another twist going forward,” Gross, who runs the world’s biggest bond fund, said in a recent “InBusiness with Margaret Brennan” interview on Bloomberg Television.

The Fed purchased $2.3 trillion of debt in two rounds of s- called quantitative easing that have become known as QE1 and QE2 as part of its efforts to support the world’s biggest economy. The Fed is replacing $400 billion of short-term debt in its portfolio with longer-term Treasurys to limit borrowing costs and counter risks of a recession.

Pimco’s $252 billion Total Return Fund reduced holdings of Treasurys last month for the first time since February 2011, when it cut its stake in the securities to zero.

Gross lowered the proportion of U.S. government securities in the fund to 37 percent of assets from 38 percent in January, according to a report on the company’s website. He raised mortgages to 52 from 50 percent.

Pimco, a unit of the Munich-based insurer Allianz SE, managed $1.35 trillion of assets as of September.

The five-year notes that Russia plans to sell offer more value than U.S. Treasurys of the same maturity, Gross said.