The biggest banks in the U.S. will begin to release 2014 first quarter results next week and investors like Jim Cramer and Stephanie Link will watch to see where banks are making their money. Cramer says the low interest rate environment has hurt banks. Link says revenue from merger and acquisition activity should be higher. Link says bank stocks appear to have cheap valuations and balance sheets look strong which would make the a buy. Cramer says changing yield curve should should also help.