Six months back, CoreLogic was bullish on the outlook for due-diligence work tied to jumbo securitizations. But earlier this month, the publicly-traded mortgage vendor shuttered its due-diligence unit, giving layoff notices to almost 70 workers. Another 40 or so full-timers will likely lose their positions in the next few months as the division winds down. Although the firm declined to discuss the reasons behind the pullout, competitors say the anticipated boom in jumbo securitizations hit a brick wall in the spring when rates spiked and investors began to shy away from the AAA pieces of those securities. In other words, the sour short-term outlook for due-diligence firms scouring for work on non-agency loans is resulting...