Fed's message on portfolio trimming: prepare, don't fret

SAN FRANCISCO/NEW YORK (Reuters) - Federal Reserve policymakers are putting markets on notice that the central bank's $4.5 trillion balance sheet is back on the agenda in an apparent effort to give investors time to prepare for changes rather than to signal any action is imminent. The Fed amassed the bonds during and after the financial crisis to inject cash into the economy and put downward pressure on long-term rates, and has been keeping its portfolio steady since December 2013. While the Fed