Companies are giving weaker earnings guidance than usual, raising the question of whether stocks could be in trouble.

Over the last five years, on average, 62 percent of Standard & Poor's 500 Index companies that have offered earnings-per-share (EPS) guidance have produced forecasts below the mean EPS estimate of Wall Street analysts, CNBC reports.

But for the second quarter, 86 of the 106 S&P companies giving guidance have predicted EPS below the mean Wall Street estimate, according to research firm FactSet. That translates to 81 percent.

Editor's Note: Economist Warns: 50% Unemployment, 100% Inflation Possible

But does this mean trouble is brewing in the corporate world or simply that companies are lowballing their guidance so that they can exceed it?

"There's certainly a trend where companies tend to be more conservative when giving guidance, so that they can turn around and beat that number," John Butters, senior earnings analyst at FactSet, told CNBC.

But "if we finished here, it would be the quarter with the highest percentage of negative pre-announcements since we began tracking the data in 2006."

Wall Street analysts aren't exactly doing jumping jacks either. They have slashed their estimate of second-quarter earnings growth to 1.3 percent for the S&P 500 from 4.4 percent previously.

Sam Ro of Business Insider puts the implications for stocks in colorful terms. "Some warn that this trend of stock prices rallying with no earnings growth is getting dangerous for investors," he writes.

"But for now, it'll continue to make the bears look like fools."

Editor's Note: Economist Warns: 50% Unemployment, 100% Inflation Possible