Mortgage originations by the nation's largest four banks fell 20.4% in 2011 to a combined $717 billion from $902 billion in 2010, according to HousingWire analysis of the company's financial statements. Excluding Bank of America (BAC), overall mortgage production among the big banks fell 6.3% in 2011. Citigroup's (C) home loan production remained flat throughout the year as it wrote $63 billion worth of mortgages in 2011 after writing $62 billion in 2010. The 2% increase makes Citigroup the only bank of the top four to increase mortgage origination throughout the year. JPMorgan Chase's (JPM) mortgage originations fell 6.4% to $146 billion from $156 billion in 2010. Wells Fargo (WFC), the nation's largest mortgage lender, experienced a 7.5% slowdown in production to $357 billion from $386 billion in 2010. BofA's mortgage production cratered 49.1% to $152 billion from $298 billion in 2010. The Charlotte, N.C.-based bank reported $1.4 billion in profit for 2011, down 36% from earnings of $2.2 billion the prior year. The bank said the closing of its correspondent lending channel and a declining market share cut it into its production earnings. Credit conditions in the U.S. are loosening as 2012 begins, according to Capital Economics. "We expect this to continue, supporting home sales and putting a floor under house prices," analysts at the Toronto-based research firm said. "But any improvement in credit conditions won’t be significant enough to generate actual house price gains and could be rapidly reversed if the fallout from a eurozone break-up is worse than we anticipate." The nation's fifth largest bank, Ally Financial (GJM), has yet to report fourth-quarter and 2011 results. Write to Justin T. Hilley. Follow him on Twitter @JustinHilley.