The Federal Home Loan Bank of Chicago has turned up the competitive heat on Fannie Mae and Freddie Mac by orchestrating the first security offering backed by mortgages originated by FHLBank members. But even with the issuance of the first MPF Shared Funding mortgage-backed security, relatively little is still known about the structure or workings of the novel offering. And this has frustrated some FHLBanks who that have privately complained that the Chicago Bank