Earnings season has the power to lift companies and instill optimism in investors -- but it also has the ability to take down stocks with the force of a hurricane. The Dow Jones Industrial Average (^DJI 0.16%) is getting a taste of that today, as a poor quarterly report from one of America's biggest banks has taken the index down about 130 points, or 0.88%, as of 2:15 p.m. EDT. Only a handful of Dow stocks are in the green today. Let's catch up on what you need to know.

Bears attack the financial sector
Bank of America
(BAC 0.92%) has taken the entire index down as its shares plummet 5.8%. The company whiffed on earnings today, reporting per-share profits of $0.20 -- three pennies below what analysts were expecting. B of A's stock has done well in the past year, but today's drop will put a damper on investor optimism. The company's revenue from both trading and mortgage originations fell in the most recent quarter, and while wealth management and investment banking performed better, the bank will face increased scrutiny from Wall Street over today's miss. Still, B of A said it had improved cost-cutting in the most recent quarter -- a bright spot amid the disappointment.

The miss has dragged down the banking sector as a whole today, dragging down fellow Dow member JPMorgan (JPM 0.50%). Shares of the bank have fallen 3.2% to rank near the bottom of the index despite the company's standout quarterly report last week. JPMorgan looks to be on better footing than B of A despite its recent spate of regulatory and legal woes: The company reported record net profit of $6.5 billion for the first quarter, showing significant year-over-year growth even as revenue fell. JPMorgan still faces lawsuits over its "London Whale" scandal that will keep regulatory scrutiny fixed squarely on the company, but for now the bank is performing well enough for Wall Street's expectations.

The same can't be said of another big loser on the Dow, industrial giant Caterpillar (CAT 0.56%). This stock has been hammered over the course of 2013, and shares are down a further 1.7% today. China's slowdown has crippled Caterpillar's fortunes, and the country's disappointing GDP report showing only 7.7% growth in the first quarter didn't help the company's outlook.

With most of Caterpillar's sales coming from overseas, this company desperately needs high-growth markets such as China and Southeast Asia to pick up a head of steam and kick off a new wave of construction and infrastructure spending. The U.S. housing market's rebound should help Caterpillar, but that alone won't be enough to turn around the company's fortunes.

Not all stocks are suffering from the financial sector's fall today. Johnson & Johnson (JNJ 0.87%) leads a resistant few gainers on the Dow today, with shares of the health care giant gaining 0.7%. The company got a boost today after a jury ruled in its favor in lawsuits over its ASR hip implant recall back in 2010. That's a good sign for J&J, which has suffered numerous headaches and thousands of suits over its hip devices recently. It's also a boon for investors, who were already cheering J&J's expectation-beating earnings report yesterday. For Johnson & Johnson, it's so far, so good in 2013.