Banks are using a little-known tactic to help pay bonuses, deferred pay and pensions they owe executives: They're holding life-insurance policies on hundreds of thousands of their workers, with themselves as the beneficiaries.

Banks took out much of this life insurance during the mortgage bubble, when executives' pay -- and the IOUs for their deferred compensation -- surged, and banking regulators affirmed the use of life insurance as a way to finance executive pay and benefits.

Bank...