Source: Flickr / PhilipC.

This March is a critical month for bank investors, as it brings us the results from long awaited stress tests both in the U.S. and overseas. Dividend, value, and growth investors all have something to gain -- or lose -- based on developments this month and I'll take a look at two key sets of stress tests.

Greek banks
For the past few years, Greece has been burdened by recession and record levels of unemployment. Both this economic slowdown and a subsequent drop in property values tore huge holes in bank balance sheets, requiring a 28 billion euro bailout last year. This recapitalization left the Greek government with majority stakes in all of Greece's four major banks.

The question for 2014 has been: How much more money will these four banks need? We now have the results -- and it's time to take a look.

As expected, Eurobank requires the most additional capital at almost 3 billion euros, an amount likely to be raised as the government seeks out new private investment for the bank. Greece's largest lender, National Bank of Greece (UNKNOWN:NBG.DL), requires 2.2 billion euros of additional capital. Greece's other two major lenders, Alpha Bank and Piraeus Bank, require capital increases of 262 million euros and 425 million euros, respectively.

National Bank of Greece, the most accessible Greek bank for U.S. investors, was quick to respond to the stress test results noting that it will not have to issue additional shares to raise capital. This removes the looming fear of share dilution and is a strong positive for the bank. Instead of issuing shares, NBG is targeting asset sales and internal improvements to bolster its capital levels.

U.S. banks
For those not involved in Greek banks, stress tests are still coming to a market near you. The Federal Reserve has set March 26 as the date for release of stress tests for the 30 largest American banks.

American banks are in better shape than their Greek counterparts, and recapitalization forced share dilution is not considered a major risk here. Instead, investors are looking out for indications on dividends and buybacks.

Closely watched here are Bank of America (NYSE:BAC) and Citigroup (NYSE:C). Both banks pay dividends on par with their own FDIC insured accounts. But positive stress test results could make these penny dividends a thing of the past. B of A and Citigroup are both eager to attract more dividend investors, and an increase into the 1%-2% yield range would help win some back.

Buybacks are also worth watching here. Both banks trade below book value. meaning share repurchases at these levels would help increase earnings per share and grow book value. Citigroup even trades below tangible book value, making repurchases at these levels even more accretive.

Stress filled month
Investors have already seen the results of the long awaited Greek bank stress tests and the overall positive outcome for National Bank of Greece. Now, U.S. investors await the results from the largest American banks. Investors should be on the lookout for dividends, buybacks, and capital ratios to see how they affect their investment positions.