Fact: 30-year-fixed mortgage rates dropped below 4 percent for the first time on record, according to Freddie Mac, which has tracked rates since 1971. Yet, the stats show that Americans have not responded by rushing to buy houses.

Fact: Real estate investment trusts (REITs), a breed of stocks that pool investments in underlying real estate like hotels or apartments, dropped 13.3 % in the 3rd quarter, marking the first time in two years that the sector has gotten hammered.

Fact: The “conforming loan limit” — the point at which mortgages are supported by quasi-governmental agencies — dropped this past weekend by around $100,000, and rates for medium-sized loans jumped about one-quarter of 1 percent.

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Fact: In an analyst’s report cited by Businessweek, Merrill Lynch cut its forecast for issuance of commercial mortgage-backed securities in 2011 from $45 billion to $25 billion, fairly close to the $20 billion amount that’s already been issued so far this year.

Add up all these facts and pause a moment. The sound you hear is gears grinding, without the grease of credit. It’s always a tough pronouncement to say that credit is tightening, because lenders — who are the parties who could really confirm such an action — never want to hang a “gone fishin'” sign on the office door.

Yet on the commericial side, the skid in the mortgage-backed securities market and the decline of REITs points to a future without much liquidity — probably Wall Street being nervous about European debt problems. Of course you didn’t need me to tell you that; anyone who owns a share of stock understands that Wall Street is pretty jittery these days.

What about the residential real estate market? The Mortgage Bankers’ Association’s weekly survey of mortgage applications showed a decline in demand this week, dropping by 4.3% on a seasonally adjusted basis. Since applications had popped the week before, it looks like the demand side is healthy — but shouldn’t the lowest rates in four decades be stirring up even more of an appetite?

Lawrence Yun, the chief economist of the National Association of Realtors (an organization I’ve been a member of), argues that lack of lending is constraining home sales. August pending home sales numbers were released last week, and the numbers were up from last year, which is positive. Still, Yun had some sharp words for lenders: “We continue to experience a pattern in which financially qualified home buyers, willing to stay well within their means, are being denied credit – a factor in elevated levels of contract failures,” he said in a release. “Based on the improving fundamentals of population growth, some job additions, rent increases and higher stock market wealth, we should be seeing existing-home sales closer to 5.5 million, but are expecting just over 4.9 million this year. The unnecessarily restrictive mortgage underwriting standards are attenuating the housing recovery and are a risk factor for the overall economy.”

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More broadly, it’s not just real estate that’s being affected. A survey conducted for FICO, the credit score people, by the Professional Risk Managers International Association tells a fascinating story. Bankers, it finds, expect a “credit gap” to continue between the amount of credit small businesses request and the amount that they receive.

Specifically, 57 percent of bankers in the survey expected the amount of credit requested by small businesses in the next six months to increase, but only 34 percent of those same bankers expected the amount of credit that is actually extended to small business to increase.

Since small businesses are responsible for half of America’s private sector jobs, their lack of access to funds is — like the troubles in commercial and residential real estate — a drag on the recovery.

It does seem like one solution to this anemic economy would be to bring lending back. Bankers, can you spare a dime?