The slow-moving US economy could cause the Federal Reserve to renew liquidity programs set to expire this month, bond giant Pimco's Bill Gross told CNBC.

Bill Gross

With the Fed's buying of mortgage-backed securities and other programs unwinding, the "new normal" scenario that Pimco has forecast could force the central bank's hand, said Gross, the co-CIO and manager of the world's largest bond fund.