 Markel Gayner Asset Management Corp., the investment arm of insurance company Markel Corp. MKL , Financial, disclosed in a regulatory filing that its top five trades during the first quarter included the closure of its holdings in Mohawk Industries Inc. MHK , Financial and Albemarle Corp. ALB , Financial and boosts to its holdings in Dollar General Corp. DG , Financial, Allstate Corp. ALL , Financial and FedEx Corp. FDX , Financial. 