Federal Reserve officials have agreed to sell some of the central bank's $1.1trn portfolio of mortgage-backed securities, but many are undecided on how soon or how aggressively to do so, according to several people familiar with the matter. Many Fed officials want to sell the securities after the central bank begins to raise short-term interest rates and tighten financial conditions, as the sale could push down prices of the securities and push up mortgage borrowing costs. Richmond Fed President Jeffrey Lacker said earlier this week that the Federal Reserve should consider selling some of the mortgage debt it acquired during the financial crisis before raising interest rates, and added that he is worried about "persistently high" inflation expectations.