There are different definitions of the supply of money, and they measure different things.
M2 would largely grow or shrink according to demand for loans at banks. I think of M2 as the supply of money that's generated by commercial banks. As there is an increasing demand for loans, banks can increase the supply of M2 by providing more loans. Those loans ultimately end up in savings accounts and other places around the economy.
Generally the demand for credit has been coming down and the M2 numbers are relatively low over historical perspectives. They are lower, but you wouldn't necessarily see those show up on our balance sheet.