We haven't even really gotten started with rate hikes and the Federal Reserve is already worried that if interest rates go up, they'll only need to come right back down again. As it stands today, any number of factors could force the Fed to reverse course (on its plan to raise rates) and ultimately cut rates: A shock to the U.S. economy from abroad, persistently low inflation, some new financial bubble bursting and slamming the economy, or lost momentum in a business cycle which, at 83 months, is already longer than 29 of the 33 expansions the U.S. economy has experienced since 1854.

What's more, among 65 economists recently surveyed by the Wall Street Journal, more than half said it was somewhat or very likely that the Fed's benchmark federal funds rate would be back near zero within the next five years. Ten said the Fed might even push rates into negative territory!

In addition to the usual suspects, there is yet another trigger that may help to keep rates low, and it stems from a highly unlikely source: Money market fund reform.