STORY: U.S. stocks see-sawed on Monday, ending essentially unchanged as investors braced for earnings from several mega-cap tech companies and a big rate hike from the Federal Reserve at its meeting this week.

The Dow and S&P 500 ended in positive territory with fractional gains, while the tech-heavy Nasdaq fell about four tenths of a percent.

Sean O'Hara is president of Pacer ETFs.

"I think what's really happening is what's been happening here lately, which is it's searching for a clear trend or direction one way or the other. You know, the tech being down is probably a reaction or in anticipation of, you know, forward guidance on some of the tech or growth year names being lower, not necessarily negative guidance, but slower earnings growth. And so that means that multiples have to continue to track and contract even further than they have. And then I think the rest of the market is sort of waiting to see what happens with the Fed this week, whether they do 75 basis points or 100 basis points, and when they ultimately release their minutes, try to get some sense for how much further they actually believe they need to go and how much more aggressively they might need to move."

In addition to the Fed meeting, this week is expected to be the busiest in the second-quarter reporting period, with results from Microsoft and Google-parent Alphabet due to report Tuesday, while Apple and Amazon earnings are set for Thursday. Shares of each of those mega-caps ended lower on Monday.

Energy stocks rose with Exxon Mobil and Diamondback Energy posting big gains as oil prices surged, bolstered by supply fears.

Shares of grill maker Weber got burned Monday, after the company said it replaced its CEO and warned that mounting inflationary and supply chain pressures could bite into its business.

And after the close, Walmart said it was cutting its forecast for full-year profit, due to higher sales of lower-margin food products and price cuts to sell inventory in the U.S., that sent shares of the nation's largest retailer down in after hours trading.