This invention provides system and methods for managing accounts of clients at customer financial entities so that deposits of up to $100,000 or greater are insured, so that interest income earned on a portion of all of the account balances may be flexibly allocated according to customer instructions, and so that withdrawals are not limited. These objects are satisfied by holding client funds at interest-earning money market deposit accounts at one or more banks or savings institutions. More particularly, this invention provides methods for receiving client transaction information, determining a net transfer of funds into or out of each client account from transaction information, causing transfer of funds from the insured, interest-bearing deposit accounts to match the net transfer of funds into or out of each client account, and allocating interest earned by the deposit accounts to clients according to customer instructions. This invention also provides systems and software products implementing these methods.