Over the weekend, many investors worried that Friday's drop in the Dow Jones Industrials (DJINDICES:^DJI) could be a precursor to a longer-term correction. That theory played out Monday morning, as the Dow fell 104 points by 11 a.m. EDT. Without any major economic data moving the market today, investors are looking forward to the beginning of earnings season this week, with reports from the aluminum and banking sectors giving the first read on the state of corporate America. Even amid the gloom this morning, Intel (NASDAQ:INTC) managed to post a solid advance, while Pfizer (NYSE:PFE) and Visa (NYSE:V) were among the worst performers in the Dow.

Source: Intel.

Intel's 1.9% gain came in the wake of an upgrade from Pacific Crest, which argued that the tech giant's enterprise-focused server and PC business is doing better than many investors give Intel credit for. Although the consumer side of the PC market has garnered the lion's share of attention among Intel bears, a reviving U.S. economy can generate greater activity from enterprise customers that are finally starting to bolster their tech spending. The same trend could help shares of many of Intel's peers, potentially lifting the entire Nasdaq after a particularly rough few days last week.

Pfizer's 2.6% drop, on the other hand, seemed somewhat odd given that the drugmaker announced over the weekend that its breast-cancer treatment palbociclib extended the amount of time patients survived without the disease progressing. Yet some investors had hoped to see even stronger results from the phase 2 trial, and Pfizer noted that while it hopes to get a faster-track approval for the treatment, it's too early to tell whether the FDA would be amenable to the idea at this point. The negative shareholder response also indicates just how much pressure Pfizer is under, especially regarding palbociclib and other drugs that investors see as potential blockbusters for the company.

Visa fell 2.7%, and its high share price had a much larger impact on the Dow than Pfizer's decline. Reports over the weekend suggested that Visa and other prominent payment networks will face increased competition from retailers seeking direct entries into the mobile-payment industry. After huge lawsuits between card companies and merchants, big retailers no longer want to share as much of their thin profit margins paying electronic-transaction fees. They see mobile-based digital wallets as a way of circumventing Visa and its peers to keep more of their revenue for themselves. With the ability to give discounts, retailers could prove a tough act for Visa to overcome in the long run.