What strategy does Bruno Verstraete recommend as the U.S. stock market experiences its best week in a year? Flee the market as fast as you can, the CEO of wealth management firm Nautilus Invest tells CNBC.

"Overall in our asset allocation, we have been pretty bearish on equities, having none – zero percent – since the beginning of April, and that has helped us quite a lot in the past few months," Verstraete said.

In early Friday trading, the Standard & Poor’s 500 Index stood near 1,330, up 5 percent in just the last five trading days.

NYSE traders (Getty Images photo)

Verstraete’s reaction: Nautilus will maintain its zero percent stock exposure through the summer, after a 60 percent weighting in January.

The firm now devotes 75 percent of its assets to government bonds and just under 17 percent to corporate bonds, with the balance in cash – three-month Treasury bills.

Verstraete is worried about Greece’s financial crisis and the possibility of contagion. "I think the answer we haven't got so far is whether or not this will be a credit event,” he says. “If it is a credit event, it will have a huge impact on the financial industry."

Not everyone feels uncomfortable with the lofty level of U.S. stocks.

"You're starting to settle into a realization that stocks are probably priced somewhere around where they should be,” Rick Meckler, president of investment firm LibertyView Capital Management, tells Reuters.