Wall Street analysts' profit forecasts are weak for the first half of 2015, and that could spell trouble for the economy.

Analysts predict earnings for S&P 500 companies will drop 4.8 percent in the first quarter, after rising 3.7 percent in the fourth quarter, according to FactSet. For the second quarter, S&P Capital IQ anticipates a 1.8 percent decline.

Each of the 10 recessions since 1945 has been accompanied by a decline in earnings growth.
And only three times during that period was there an earnings drop that wasn't accompanied by a recession, Sam Stovall, chief equity strategist at S&P Capital IQ, wrote in a commentary obtained by CNBC.

"While not an official profit recession, as no contraction in EPS [earnings-per-share] growth is currently projected [for the entire year], the full-year growth estimate is getting uncomfortably close to that threshold," Stovall said.

"And like the recognizable pair of Astaire and Rodgers, downward EPS growth trends and economic recessions also go hand-in-hand."

To be sure, actual earnings usually come in far stronger than estimates, as CNBC's Jeff Cox notes.

Meanwhile, slowing earnings growth is one factor cited by Martin Pelletier, a portfolio manager at Canada's TriVest Wealth Counsel, as a reason why the stock market may be running out of steam. The S&P 500 stood about 1 percent from its record high Tuesday afternoon.

"The high U.S. dollar and low oil prices are starting to take their toll on corporate profitability," he writes in Canada's Financial Post. Oil prices have dropped to six-year lows, and the dollar has risen to multi-year highs against a range of currencies in recent weeks.

Another bearish factor for stocks: "an over-reliance on the Fed," Pelletier says. "We are now back to the scenario where bad news economically is considered good news, as investors want the U.S. Federal Reserve to keep interest rates at ultra-low levels."

Many experts say the six-year bull market for stocks was built largely on Fed easing. And now the central bank is on its way toward raising rates, perhaps starting in September.

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