Based on volumes of activity and current cost structures of many banks, operating costs may need to fall by 20%-45% and the balance sheet by 50%-75%, through closing or selling branches, products, business lines, and even entire regions.

FORBES: How Europe's Banks Can Return To Health

Called TDABC (time-driven activity-based costing), it attempted to relate the measurement of cost to time.

ECONOMIST: Idea

Use of software like Marketo is done on a longer term, but the cost can be ratcheted up or down based on how much marketing activity is flowing through.

FORBES: JargonSpy