Although we don't believe in timing the market or panicking over daily movements, we do like to keep an eye on market changes -- just in case they're material to our investing thesis.

The Dow Jones Industrial Average (DJINDICES:^DJI) is up 44 points  to 16,461 at 1:30 p.m EST, after better than expected earnings from American Express (NYSE:AXP) helped lift top Dow stock Visa (NYSE:V). The S&P 500 (SNPINDEX:^GSPC) was down four points to 1,841.

This was been a big week for financial stocks, with Bank of America, Goldman Sachs, and Citigroup all issuing quarterly earnings reports. The financial earnings parade continued with today's Dow leader AmEx, which is up 4.65% to $91.86.

The credit card company yesterday announced that fourth-quarter profits more than doubled to $1.21 per share from $0.56 per share a year ago. That was actually below analyst expectations of earnings of $1.27 per share. Revenue also came in less than expected at $8.5 billion versus expectations of $8.6 billion.

Despite the lower than expected earnings, two analyst upgrades pushed the stock higher today. Susquehanna raised American Express from neutral to positive and raised its price target on the stock from $90 to $107. Buckingham raised its opinion from neutral to buy and its price target from $90 to $104.

American Express trades at a 33% lower price-to-earnings ratio than rivals Visa and MasterCard, as the company takes on more risk from its customers. Visa and MasterCard are payment processors and leave the credit risk to their banking partners. That said, American Express' good news is pulling up Visa -- 3.1% at last check -- on hopes that its earnings will also be positive. Visa is the largest Dow stock in terms of price -- $228.58 per share. As the Dow is structured as a price-weighted index, companies with higher stock prices move it more. 

Dan Dzombak has no position in any stocks mentioned. The Motley Fool recommends American Express and Visa. The Motley Fool owns shares of Visa. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.