Whenever the County Controller accepts a deposit of securities in lieu
of retained percentage as required by § 106 of the General Municipal
Law, he shall, as authorized by § 106-a of the General Municipal
Law, impose and collect from the contractor the service charge of one-fourth
of one percent (1/4 of 1%) of the value of the securities deposited as such
value is determined by the County Controller after consultation with dealers
in municipal securities. This charge will be accepted for services connected
with the original deposit of securities, clipping of coupons and other processing
and servicing until the termination of the contract.