Why I'm shorting this market

This story has been updated to reflect that Ron Insana is now short the market.

Tune in to Power Lunch at 1pm ET. Ron Insana will be on to discuss his move to short the market.

Recent market action has been unnerving. I'm out of stocks for the time being and I've taken short positions, betting that the market will fall. I think there's a 5 percent to 10 percent correction — or something slightly worse — coming.

I have, however, maintained a small long dollar position, via the UUP (ETF). The dollar seems to be holding its own, as the only safety trade on at the moment.

Stocks, bonds, gold, oil and other commodities are falling together, something we have not seen in a few years. I am especially concerned that, unlike previous declines, bonds are not seeing a flight-to-quality rally, something that would hold down interest rates and cushion any decline in equities.

Read MoreThese factors could exacerbate selloff: Cashin

Transportation stocks have weakened in recent days, despite a large decline in oil prices, a factor that usually triggers a rally in transports.

There's no sign of a safe-haven trade. That can often be a sign of distress. Argentina's debt default and a potential crisis in Portugal's banking system are creating contagion risk (real or imagined) in global financial markets. U.S./EU sanctions have stiffened against Russia and the Middle East remains the hottest spot on the planet.

While all this has been known, for days or weeks, markets are acting as if another shoe is about to drop and I am not interested in hanging around to find out what it is.

Read MoreCramer: 5 things wreaking havoc on this market

While some cite disappointing profit reports from a handful of companies late Wednesday as a reason for Thursday's decline, earnings are not the problem for the market. Statistics show that 75 percent of companies that have reported their quarterly results have beaten Wall Street expectations, while 66 percent have been estimates for revenue growth. Profits are up, on average, 6 percent while revenues are up around 3 percent.

We have not had a 10-percent pullback in over two years, and while I believe this remains a secular bull market, taking chips off the table, for a time, may be prudent portfolio management.

I got out of my short positions on April 25 but with market technicals deteriorating further, I'm back in. While I am not in the Faber, Schiff, Dent, "Camp Armageddon" group, I don't like the action here.

Read MoreWhat are stocks doing now? Click here for Thursday's market action.

Commentary by Ron Insana, a CNBC and MSNBC contributor and the author of four books on Wall Street. He also delivers a daily podcast, "Insana Insights," and a long-form weekly version, both available on iTunes and at roninsana.com. Follow him on Twitter @rinsana.