CLARKONOMICS: New rules intended to make money market funds safer than ever were announced today. The catch? Increased safety requirements will mean a lower return on your money.

Money market funds had long been considered just about the safest place to stash cash. During the nearly 30 years of their existence, no one had ever lost a single penny in a money market fund. They were specifically designed not to "break the buck," meaning that shares would always be valued at $1. In other words, you would get back out what you put in, plus interest.

However, one particular money market family called the Reserve Fund did break the buck last September. That caused a run on the fund and destabilized the industry when the Reserve Fund couldn't make its customers whole.

The feds had to step in with a temporary guarantee at taxpayer expense.

Today, the SEC by unanimous vote passed new rules to tighten the requirements on money market funds. These rules will now enter a period of time for comment and become the law of the land shortly afterward.

Thankfully, taxpayers will no longer have to back the interim support that the feds put in place.

And if you were one of the people who put money into U.S. Treasuries to wait out the storm -- where you're effectively earning zero -- now is the time to get back into money market funds or into an FDIC-insured savings account.