This is the price point to beware for falling oil

Oil tanks and pump jacks are seen in an oil field near Bakersfield, Calif.
Lucy Nicholson | Reuters

Many investors believe that declining oil prices are a good thing—for now—though some see $30 a barrel as the break point when the trend turns negative.

Earnings season has provided a good glimpse at how energy is impacting corporate America.

Outside the sector, this is turning into a pretty good quarter. Include energy, though, and things are fairly gloomy.

About 75 percent of companies that reported through Wednesday beat sharply lowered analyst expectations, according to S&P Capital IQ. That's come, however, amid a brutal quarter for energy companies, with the sector projected to show a 22.6 percent profit decline.

Overall, earnings for the fourth quarter of 2014 are expected to increase 4.4 percent, a number that's been drifting higher as results from 51 companies have come in.