While U.S. stocks stand at historically high valuations, valuations in foreign markets are much lower, and that makes them attractive, says MarketWatch columnist John Coumarianos.

The S&P 500 index carried a trailing price-earnings ratio of 21.24 Friday, up from 19.54 a year earlier. And Robert Shiller's cyclically-adjusted price earnings ratio (CAPE) for the S&P 500, which includes 10 years of earnings, stands at 27.1. For months it has hovered at its highest levels excluding the pre-market crash periods of 1929, 2000 and 2007.

"If the current level of U.S. stock prices is concerning, consider leaving home. Other countries’ markets are offering compelling investment bargains," Coumarianos writes.

He includes data from Research Affiliates showing 24 markets that trade cheaper than the United States. That includes the United Kingdom, Japan, Germany, Hong Kong and India.

Coumarianos expressed particular enthusiasm for British stocks

"The U.K.'s current CAPE of 12.4 is low compared to the other countries and regions, and below its own median of 14.6 using data going back to 1969," he explains. Moreover, investors shouldn’t have to worry too much about currency exposure to the pound."

Elsewhere on the U.S. stock front, though the S&P 500 stands less than 2 percent below its record high, it also stands less than 1 percent beneath its March 2 close. And that points to risk for the market, says veteran technical analyst Ralph Acampora of Altaira Ltd.

During this 4 ½-month period, "we saw several instances when the leading averages registered new highs, but only for a few days before selling off again," he told CNBC. The S&P 500 reached its all-time peak May 20.

"If we don't see new highs, it falls into this category that we're churning just like we did the last five months, and leadership is very narrow here," Acampora said. "Current leadership is in consumer discretionary and staples, financials, health-care and select technology sectors."

To be sure, Acampora still sees the S&P 500 index rising through year-end, reaching 2,250 to 2,300, up as much as 9 percent from 2,104 Wednesday. But he stressed that "we need new highs, or I'll have a problem later on."

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