With interest essentially at zero, many investors are buying riskier securities in an effort to earn larger returns. Moreover, the usual spreads between high grade and junk bonds, and between fed funds and 10 year treasuries, have collapsed. The Fed’s concern is that an unexpected rate rise might spark a panic.

Those with moderately long memories might remember the damage in the mortgage-back markets in 1994 when the Fed was more aggressive than expected. While the problem of an unexpected rate rise and ensuing panic remains, the Fed is likely to back away from forward guidance and stick to more general and less conditional comments in its formal statements. This is a safer approach – a wrong forecast is worse than no guidance.

For most of its 100 year history, the central bank said almost nothing. In the last decade or so it has become more talkative. While a return to silence is not expected, the forward guidance will be less specific. Wednesday’s statement is likely to confirm the tapering move and suggest that the Fed funds rate will remain between zero and 25 bp for the rest of this year. But nothing like, “if this happens, then we will do that…”

This article was written by David Blitzer, chairman of the index committee, S&P Dow Jones Indices.

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