Visitors wait in line to enter the new Apple Store on Fifth Avenue on May 19, 2006, in New York City.

Thanks to a blockbuster quarter that included sales of nearly 75 million iPhone 6 devices, the company helped boost corporate America's bottom line in a quarter noted mostly for companies clearing a sharply lowered bar.

The Cupertino, California-based tech giant made an outsized contribution to fourth-quarter earnings, adding nearly double its portion of the according to an analysis of figures as about three-quarters of the index has reported.

It's a good thing for Apple, because otherwise the U.S. profit picture would look a lot different.

Ultimately, Apple accounted for about 7 percent of total earnings, or $2.04, for the quarter, according to calculations from Goldman Sachs. That was more than the contribution of Exxon Mobil, Microsoft and General Electric combined.

Read MoreDominant: Apple has90% of smartphone profits

It's all the more noteworthy because Apple comprises 3.83 percent of the total S&P 500 market cap, or just more than half its earnings contribution.

The Apple numbers are significant because they exemplify the extent to which overall profit is on the decline thanks to a slump in energy profits, despite previous lofty expectations for 2015.

While the fourth quarter has seen 72 percent of companies top lowered expectations, good for a 7 percent gain overall, projections going forward are dismal.

Read MoreCramer: We need some good news overseas



Where first-quarter profits once were expected to jump 14.8 percent, they are now estimated to contract 1.48 percent, according to the most recent figures compiled by S&P Capital IQ. The second quarter looks bleak as well, with current forecasts calling for a 1.09 percent loss.

For the full year, earnings are expected to grow just 1.91 percent. Even with a customary beat rate of 65 percent to 75 percent, that would result in earnings growth in the low single digits. Initial full-year earnings projections were for 11.5 percent growth.

Most of the decline is attributable to energy, with companies hit by falling oil prices expected to post massive profit drops in the quarters ahead—including a 61 percent decline in the first quarter—before finally leveling off in the fourth quarter.

Revenue expectations are no better, with top-line growth currently put at 0.3 percent.