Deepak Narula’s mortgage-bond fund is up 39 percent this year. George Sanchez’s monthly annuity payout is down 41 percent.

The near-zero interest rate the Federal Reserve charges financial firms, as well as securities purchases that will balloon the central bank’s balance sheet to almost $4 trillion next year, have made it easier for Narula’s $1.6 billion fund to thrive and more difficult for Sanchez, a former college library director, to enjoy retirement.

Monetary policy has been indirectly, surreptitiously helping the top and hurting the bottom,” said Joseph E. Stiglitz, the Nobel Prize-winning Columbia University economist.