The long-awaited slowdown in residential originations may finally be at the doorstep of the nation’s largest banks, according to first-quarter results released over the past week by the “giants” of the industry including Bank of America, JPMorgan Chase, Wells Fargo, Citigroup and U.S. Bancorp. In general, gain-on-sale margins eroded or held steady, but most megabanks hiked the asset value of their mortgage servicing rights. And some, like Wells and U.S. Bancorp, continued to hold some of their agency-eligible mortgage originations on their books instead of selling them to Fannie Mae and Freddie Mac. “Revenues have peaked for everyone,” Brian Foran, an analyst with Autonomous, told...