. in addition , program-wide liquidity is provided by jpmorgan chase to these vehicles in the event of short-term disruptions in the commer- cial paper market ; these commitments totaled $ 2.6 billion and $ 2.7 billion at december 31 , 2003 and 2002 , respectively . for certain multi-seller conduits , jpmorgan chase also provides lim- ited credit enhancement , primarily through the issuance of letters of credit . commitments under these letters of credit totaled $ 1.9 billion and $ 3