Debt crises and stimulus measures stole the mortgage-rates show as more investors flee to U.S. Treasury debt, with mortgage giant Freddie Mac holding that rates dithered by a few percentage rates and finance Web site Bankrate.com finding a fifth-consecutive week for record lows. Homebuyers nonetheless remain on the sidelines despite all-time highs for affordability, reflecting a dearth in demand, confidence, and jobs.

Freddie Mac tallied up the latest in mortgage rates in the Primary Mortgage Market Survey, while Bankrate.com pulled from the nation’s top 10 banks and thrifts to publish a national mortgage survey. Both surveys are weekly.

First up, Bankrate.com found the benchmark 30-year fixed-rate mortgage smashing new records, falling to 4.29 percent this week from 4.32 percent last week. Freddie disagreed by offering up a 4.09-percent average for the 30-year, unchanged from last week but far below 4.37 percent seen over the same time last year.

For the 15-year loan, the GSE bore witness to a decline from 3.44 percent last week to 3.42 percent this week, a far cry from 3.82 percent seen in September 2010. The finance Web site saw a fall from 3.44 percent last week to 3.42 percent this week.

Speaking with MReport, Greg McBride, a senior financial analyst with Bankrate.com, says that “mortgage rates have yet to hit bottom. After setting records for 5 weeks in a row, the Fed’s introduction of Operation Twist promises to bring them still lower.”

Both Freddie and Bankrate.com recorded approximately the same rates for 5-year Treasury-indexed adjustable-rate mortgages (ARMs).

The former noted a 3.02-percent ARM, a few percentage points above 2.99 percent seen last week, albeit far below 3.54 percent observed in 2010. The latter noted a decline in 5-years to 3.05 percent this week from 3.07 percent last week.

The GSE also acknowledged a 2.82-percent average for 1-year ARMs, up from 2.81 percent last week but more than a few percentage points below 3.46 percent seen over the same period in 2010.

Commenting on the figures, Frank Nothaft, VP and chief economist for Freddie, said in a statement that a “sluggish economy and investor concerns over the European debt markets” largely left mortgage rates unscathed over this week.

He drew a dismal portrait of mortgage markets and the economy at large, citing a Fed report that claimed approximately $150 billion in lost net worth for households, a 5-percent decline in annual rates for new housing starts, and shaky homebuilder confidence, as more recently reported by the National Association of Home Builders/Wells Fargo Housing Market Index.

In a statement, Bankrate.com shifted interest to the Federal Reserve, which announced Wednesday that it plans to scoop up $400 billion in short-term Treasury debt and sell it to shore up long-term government bonds.

“[T]o get the most economic impact out of low mortgage rates,” the Web site wrote, “the pool of prospective refinancers needs to be expanded.”

Bankrate.com credited underwater mortgages, homeowners with second-liens loans and mortgage insurance, and lender liability worries as “formidable impediments to refinancing” that could sour the Fed buy-up and selloff.

McBride adds that record lows for mortgage rates, while “enhanc[ing] the appeal of refinancing,” stays out-of-reach for homeowners with a “lack of equity or… who own more than their homes are worth.”

He affirms a past statement he made to MReport about the Home Affordable Refinance Program, the loan-to-value thresholds for which he says federal officials should raise to allow more homeowners to take advantage of current rates.

As for the Fed? McBride says that “low rates can only do so much. People that are concerned about their job security won’t buy houses regardless of low rates.”

Speaking with MReport, Nothaft concurs, saying, “Right now families are feeling a little bit uneasy about their financial wellbeing. They’re worried about losing their job.

“In an environment like that, where the household sector as a whole is feeling very nervous and unsure, they’re going to be reluctant to make any big purchases,” he adds.

His predictions for mortgage rates: Nothaft expects yields and rates to remain low over the “next few months” but pick up in 2012.