The stock market underwent a choppy session of trading on Monday as investors tried to reconcile rising tensions with Russia with encouraging economic data and a flurry of earnings reports. While Wall Street ended on a mixed note, there wasn't much to reconcile for National Oilwell Varco (NYSE:NOV), (NYSE:CRM), and Newmont Mining Corp. (NYSE:NEM) shareholders, as the stocks finished as the three worst performers in the S&P 500 Index (SNPINDEX:^GSPC) today. The S&P 500 as a whole ended with a 6-point, or 0.3%, gain, closing at 1,869.

National Oilwell Varco, the $33 billion Houston-based oil rig-maker, saw shares take a nasty 7.4% stumble on Monday. On the face of it, the pullback seems surprising, since the company reported first quarter earnings that beat Wall Street estimates today. The company barely missed revenue forecasts, logging sales of $5.78 billion to analysts' hopes of $5.79 billion, but the real kicker came in National Oilwell Varco's talk of the future. It expects rig sales to taper off as the year wears on, with its record backlog of $16 billion easing to a mere $14 billion or $15 billion come New Year's. 

Shares of, a leading name in web-based sales generation and management, also had a rough go of it today, plunging 7%. The odd thing about Salesforce's decline today is that it wasn't clearly predicated on disappointing numbers or projections. Instead, shares are in a momentum-based freefall, one that's given shares a 12.4% haircut in the last five trading days. Stocks like Salesforce, with lofty valuations (70 times forward earnings) in hot-button industries (cloud computing), have been skating on thin ice for the last few months as institutional investors have started de-risking their portfolios in favor of less speculative plays. 

Newmont operations in Peru. Source: company website.

Lastly, shares of Newmont Mining lost 6.7% today, as talks of a merger with Barrick Gold fell apart, degenerating into a dirty game of PR bashing. Had the two companies merged, the new entity would form a $32 billion global gold-mining empire with production facilities in dozens of countries, creating new cost efficiencies from the distributed geographical locations of the company's mines. Location to the end consumer is extremely important in the materials sector, since shipping large amounts of heavy, sometimes unwieldy cargo across the world can cost a fortune. Instead of sharing the advantages offered by a merger, Newmont Mining and Barrick are left to compete with each other and point fingers as to who was responsible for the breakdown in talks. Both stocks lost major ground today, but it was the smaller Newmont that bore the brunt of the damage.