Banks must identify and build strong relationships with funding providers. In particular, banks must maintain a solid and close relationship with its 25 largest depositors on an ongoing basis, to ensure that the bank has the ability to obtain funds in case of need (e.g. during events of stress), to prevent and/or limit a bank run-off and to safeguard its major sources of funding. Nevertheless, banks must take a prudent view of how such relationships may be strained in times of stress. In the formulation of stress scenarios and contingency funding plans, banks must take into account possible situations where funding sources, including its 10 largest depositors, may dry up and markets may close, and where market perceptions of a bank's financial position may change.