Over the next six months Citi (C)JPMorgan Chase (JPM) and Wells Fargo (WFC) are expected to exhaust their own supply of Home Affordable Refinance Program eligible borrowers.

However, the remaining pool of homeowners still eligible for HARP will lead to pressure for an extension past the Dec. 31, 2013 deadline, according to Deutsche Bank (DB).

At the end of 2011, 45% of the outstanding borrowers in 6% pools were HARP-eligible. Since then, Chase and Wells Fargo are closer to this limit than any other major lenders, stated analysts Doug Bendt and Jeff Ryu in report to investor clients. 

Since March, composition of HARP lending has changed considerably due to agencies making their automated underwriting systems more largely available.

The market shares of Wells, Chase and Citi declined to 23% in October, compared to 46% in July. Over the same time span, Bank of America(BAC) tripled its share to 13%, compared to 4%. 

However, all other lenders were the “big winners” with about a market share of 65% in October.

Click on the chart for early HARP adopters lose market share. 

A shift in lenders’ productivity is a big result of the market share change. After many months of unproductivity, Bank of America’s efficiency jumped sharply over the past two months, which virtually closed its gap between Chase and Wells.

A wave of mortgage applications are expected to close throughout the rest of November and into December because of a sharp drop of 3.88% mortgage rates in August to less than 3.50% in September.

A greater portion of the applications are likely to have refinanced non-HARP eligible loans this month because the refinancing incentives change most on a percentage basis for borrowers with “large enough” incentives, according to the report.

The dollars outstanding of the combined HARP- eligible collateral for Wells, Chase and Citi is less than that of Bank of America. The combination of all other lenders accounts for about 70%.