(3) If a participant of a registered clearing agency has a fail to deliver position at a registered clearing agency in a threshold security for thirteen consecutive settlement days, the participant shall immediately thereafter close out the fail to deliver position by purchasing securities of like kind and quantity: (i) Provided, however, that a participant of a registered clearing agency that has a fail to deliver position at a registered clearing agency in a threshold security on the effective date of this amendment and which, prior to the effective date of this amendment, had been previously grandfathered from the close-out requirement in this paragraph (b)(3) (i.e., because the participant of a registered clearing agency had a fail to deliver position at a registered clearing agency on the settlement day preceding the day that the security became a threshold security), shall close out that fail to deliver position within thirty-five consecutive settlement days of the effective date of this amendment by purchasing securities of like kind and quantity;