Earnings season churns on around the market today, but disappointments from some top names have smashed stocks into the red to close the week. The Dow Jones Industrial Average (DJINDICES:^DJI) lost 160 points as of 2:30 p.m. EDT, with only a few member stocks in the green. Visa (NYSE:V) has led the Dow's drop with an outlook that disappointed investors, while Microsoft (NASDAQ:MSFT) failed to hold on to gains. Let's catch up on what you need to know.

Visa's Russia problem

Source: Wikimedia Commons

Visa's stock has nosedived by 4.5% so far today despite a relatively strong fiscal second-quarter earnings report from the credit card giant. The company's earnings beat analyst estimates by gaining 26% year over year, although Visa's revenue fell below projections. Transaction growth helped Visa's performance, with U.S. transactions gaining roughly 8% for the quarter to reach $690 billion. However, investors soured on the stock after the company warned that revenue growth could fall further in coming quarters, particularly after Visa cut off services to a pair of Russian banks amid increasing Ukraine-related tensions between the U.S. and Russia. Furthermore, the strength of the U.S. dollar could crimp revenue growth even further in the near future, according to the company.

Unfortunately, with Russian and American politics at a standstill, it's unlikely that Visa's concerns over the country's impact on its finances will be resolved soon. With 100 million cards in Russia, any deepening sanctions against the nation would be a big blow. The company still expects revenue growth of between 10% and 11% for the year, although with revenue projections riding on fluid factors such as Russia and the dollar strength, it's best to play it cautious with this stock.

Microsoft's stock dipped from the green to just under breakeven, which also isn't helping the Dow, but the company's earnings took a far different tone than Visa's downbeat display. While profit and sales fell year over year, Microsoft's bottom line topped analyst estimates and reinforced Wall Street's upbeat confidence around new CEO Satya Nadella. The personal computer sector's fall has continued to haunt Microsoft, as PC sales declined by another 4.4% for the quarter.

In good news for investors, however, the company has finally begun to take a strong step into mobile, as Surface tablet sales picked up 50% year over year. Microsoft also closed its $7.5 billion acquisition of Nokia's device division today. The company has had up-and-down fortunes on the hardware front, but the gain in Surface sales is promising for Microsoft's venture into smartphones.

If nothing else, Microsoft's phones in the future should provide a platform to better deliver the company's software and features to customers, much as the Surface has done, without relying on third-party devices -- and thus capturing more revenue for the company. Microsoft's recent decision to provide its Office software to Apple iPads paid off in a big way, but if the company is going to be serious about its hardware push, its foray into smartphones needs to trump the initial tepid launch of the Surface into the tablet market. With Nokia selling more than 250 million handsets in 2013, there's a strong foundation for Nadella and Microsoft to work with.