Both JPMorgan Chase (JPM) and Wells Fargo [stock"> predict reduced mortgage-related profit margins for the rest of the year, in addition to already lower profits off home loans, according to an article in the Huffington Post. 

Banks willingness to lend is based off their ratio of loans to deposits. Following that guideline, JPMorgan's enthusiasm for lending fell last quarter to 60.6%, the lowest level in at least five years.