How do banks manage liquidity risk?

"We report evidence from the equity market that unused loan commitments expose banks to systematic liquidity risk, especially during crises such as the one observed in the fall of 1998. We also find, however, that banks with higher levels of transactions deposits had lower risk during the 1998 crisis than other banks. These banks experienced large inflows of funds just as they were needed -- when liquidity demanded by firms taking down funds from commercial paper backup lines of credit peaked. Our evidence suggests that combining loan commitments with deposits mitigates liquidity risk, and that this deposit-lending synergy is especially powerful during period of crises as nervous investors move funds into their banks"--National Bureau of Economic Research web site.