Deposit Migration

The movement of customer cash from low-yielding bank accounts to higher-yielding alternatives like money market funds.

Deposit migration occurs when bank customers actively move their cash out of standard, low-interest checking or savings accounts and into higher-yielding financial instruments. This behavior typically accelerates in a rising interest rate environment as the gap widens between what banks pay on basic deposits and what the market offers in yield. Customers may migrate their funds internally to the bank's own higher-yielding certificates of deposit (CDs), or externally to money market funds, Treasury bills, or competing institutions. For investors, particularly those analyzing bank stocks, deposit migration is a critical headwind. It forces banks to either raise the interest rates they pay to retain customers (increasing their funding costs) or lose the deposits entirely, which shrinks their lending capacity. Both outcomes compress the bank's net interest margin and hurt overall profitability. When analyzing this trend, investors monitor the deposit beta, which measures how much of a benchmark rate hike a bank passes along to its depositors. A high rate of deposit migration indicates that a bank has weak pricing power and must pay up to keep its balance sheet funded, whereas low migration suggests a sticky, loyal customer base that provides cheap, stable funding.

Bank A has $100 million in non-interest-bearing deposits. Due to rising interest rates, customers migrate $30 million of these funds into high-yield CDs paying 4.00% and another $10 million out of the bank entirely. The bank must replace the lost $10 million with wholesale funding costing 5.00%. The bank's annual funding cost for this $40 million portion of its balance sheet rises from $0 to $1.70 million (calculated as ($30 million 0.04) + ($10 million 0.05) = $1.20 million + $0.50 million).