Is the US headed for negative interest rates?

Most of us have trouble conceptualizing negative numbers when we first face them in middle school. But in the adult world, negative numbers are becoming an increasingly normal part of the equation when it comes to interest rates.

In Europe, negative interest rates have shown up in credit markets for the better part of a year as investors give up positive returns for a modicum of safety. The return of principal has become more important than the return on principal.

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US Treasury in Washington, DC.

For example, it has become quite common for investors to pay the Swedish and Swiss governments to hold their cash, which is how we define negative interest rates. Investors get less than zero to park their money in bills and notes.

Lest you think this is only an overseas phenomenon, The Wall Street Journal recently reported that the U.S. government has held 46 Treasury-bill auctions since 2008 in which yields have been zero. In recent months, yields on 3-month bills have carried no yield twice, something the U.S. hasn't seen in modern memory.

Is this an anomaly or a precursor of what's to come of Federal Reserve policy in the months ahead?

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Investors have been holding their breath over the last several months, waiting for the Fed to raise official interest rates above zero, where they have been since the end of 2008, at the very depths of the financial crisis.

The Fed has held off raising them ever since, first to reflate the U.S. economy, and then later to avoid tightening the supply of money as the global economy stumbled in 2011 and, most recently, this past summer. The wait may prove longer than expected, given China's slowing economy, falling domestic and global inflation and market disruptions that have given the Fed pause.

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Narayana Kocherlakota, president of the Minneapolis Fed, said in an interview on Oct. 8, that the Fed should consider pushing rates below zero to help further improve the employment picture and to drive inflation back toward the Fed's stated two percent target, which it has missed for the past six years.

Kocherlakota, seen as the most "dovish" Fed member, who does not have a vote on the policy-setting arm's rotating panel this year, has been joined by a chorus of Fed officials, in recent weeks, who have been surprisingly outspoken in their opposition to a rate hike this year.

Those pushing for a rate hike are falling into the minority once again, after expressing near unanimity for a need to get off the so-called "zero bound" before 2015 drew to a close.

So, how does the Fed get to negative rates? The central bank can undertake certain measures that would punish banks, for instance, for holding their excess reserves at the Fed.

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Right now, the Fed pays banks a quarter point on the money they deposit at the Fed, of which there is more than $2.5 trillion sitting idle. If the Fed eliminated that payment, or more aggressively, charged banks to hold their money, the banks would withdraw it immediately in order not to lose money on their cash holdings and, hopefully find better things to do with it, like making more loans.

In extreme circumstances, the Fed could do the same to consumers, forcing them to spend rather than save, thereby juicing the economy. However, that would be a game-changing moment in the history of monetary policy that would likely have broad political implications and could provoke Congress to limit the powers of the central bank.

For now, though, expect more Treasury auctions to go off at zero, even though recent sales have seen yields jump on worries that Congress won't raise the debt ceiling and allow the government to default on its outstanding debt.

Political risk aside, with the deficit falling to $412 billion in the fiscal year just ended, (just 2.4 percent of GDP), official short-term rates at zero and Treasury yields there as well, the government is getting enormous relief from servicing its declining debt burden.

That's the good news. The bad news is that you may have to find another spot to park your cash while you wait ever longer for the normalization of interest rates to begin.

Commentary by Ron Insana, a CNBC and MSNBC contributor and the author of four books on Wall Street. Follow him on Twitter @rinsana.