Willis Lease Finance Corporation through its subsidiaries is a lesser of commercial aircraft engines. The Company engaged in acquiring and leasing pursuant to operating leases, commercial aircraft engines and related aircraft equipment and the selective sale of such engines. As of December 31, 2011, the Company had a total lease portfolio consisting of 194 engines and related equipment, 13 aircraft and three spare parts packages with 71 lessees in 37 countries. As of December 31, 2011, the Company managed a total lease portfolio of 26 engines and related equipment for other parties. The Company also seeks, from time to time, to act as leasing agent of engines for other parties. The Company is the servicer and administrative agent for Willis Engine Securitization Trust (WEST). Its engine portfolio consists of noise-compliant Stage III commercial jet engines manufactured by CFMI, General Electric, Pratt & Whitney, Rolls Royce and International Aero Engines.