[Update 1: adds eMBS research] As the rate of refinancing begins to abate, securitization researchers at Barclays Capital are expecting the recent drop in Fannie Mae (FNM) 30-year paydowns to continue, eventually reaching a 10-15% rate overall. Mortgages that are currently pooled for securitization are showing delinquency buyouts for the first time, according to a strategy report by the firm. This trend is also likely to accelerate as more mortgages are removed from the pools. Constant prepayment rates are also expected to jump in 30-year mortgages, especially in the 2006-7 vintages. Month-on-month, some refinancing indices declined 51%. "But 30-year [Fannie] speeds only dropped 21% because of the significant build-up in originators' pipelines," the report reads, "and many borrowers who locked in low mortgage rates in April and May still had time to exercise their options to close." Such developments are possible despite rising mortgage rates due to improvements in the Home Affordable Refinance Program (HARP), they add. Internet-based analytics firm eMBS, also released information echoing the Barclays findings. July prepayments for fixed-rate pools decreased for all 3 agencies. They report drops in prepayments for Fannie Mae (as well as Freddie and Ginnie), with 30-years down 4.8% to 18.2% CPR and 15-years off 2.7% to 16.4%. Fannie Mae fixed rate issuance also decreased by $45B to $71B, "as there appeared to be no securitizations of Fannie Mae's loan portfolio in July that would account for $35B of the decrease," said the eMBS research report. Write to Jacob Gaffney.