U.S. mortgage bonds without government backing held near the highest prices in two years last week even as sales soared to the most in more than a month. Dealers asked for bids on about $7 billion of the securities, up from less than $2 billion the previous week as “investors sought to take profits or clean up their balance sheets,” according to JPMorgan Chase & Co. analysts. “Pricing remained more or less flat through the heavy volume, indicating that there is strength at these levels,” the New York-based analysts led by Edward Reardon and John Sim wrote in a Sept. 17 report.