MKM's chief market technician, Jonathan Krinsky, says he is more cautious on the market than he's been in more than a year, arguing in a weekend note that "the scale is slowly tipping in favor of the Bears."
Fewer than half of the stocks in the Russell 3000 index, which represents 98 percent of U.S. stocks, are trading above their 200-day moving average, Krinsky said in his note. "Market internals continue to deteriorate," he said. "We find ourselves much more cautious than we have been at any point in the last 13 months."
Market breadth has deteriorated, he said, recommending that investors sell mid- and small-cap stocks in preparation for a short-term sell-off.
"There's less participating stocks in uptrends," Krinsky told CNBC's "Halftime Report" on Monday. "When you get more stocks that are in downtrends than uptrends, it's hard for the market to go up."
"There's just a lot of things under the surface that are not quite as strong as they've been in the last 12 to 14 months, so I think it's a time to look at the portfolio, maybe take some risk off."
Signs of a correction are more clear after the Dow Jones industrial average closed out its second straight week of losses last Friday after shedding 274 points in its biggest one-day fall in three months on Thursday. Investor concerns have weighed on the index, with President Donald Trump's pro-business aspirations potentially hindered by a CEO exodus from Washington. Many portfolio managers are considering cashing in on the year's growth until now.
Some Wall Street researchers are already preparing for a market correction of up to 10 percent in the next few weeks.
"I think what you want to do at this point is weed out the weak stocks," he added. "Stick with some of those leadership stocks. It's not a time to be bottom-fishing in the small caps."