The beginning of the fourth quarter usually signals the start of the busy season for multifamily transactions, with lenders inundated with loan requests and dealmakers inseparable from their cell phones.

But if September is any indication, that likely won’t be the case this year.

September 2008 was one of the slowest months for U.S. commercial property sales since the period immediately following the terrorist attacks of Sept. 11, 2001.

“There was more activity after Sept. 11, 2001, than this September,” said Dan Fasulo, managing director of market research firm Real Capital Analytics. “We’ve tracked about $1.5 billion in apartment sales this September. In October 2001, we had $2.3 billion worth of apartment sales.”

At press time, the company had not finalized its September numbers. But if the numbers hold, it would continue a dismal year. There was about $47.1 billion in apartment transactions this year through Sept. 1, down about 49 percent compared to the same period in 2007, according to Real Capital Analytics.

The lack of debt liquidity on the market is sending a chill through the multifamily industry, which had enjoyed a sort of immunity from the credit crunch through much of 2008 because of the presence of Fannie Mae and Freddie Mac. While the agencies are still providing debt to the multifamily industry, the shocking turmoil in the capital markets has severely stalled the transaction market.

The credit crunch is creating downward pressure on pricing, and in general, the only sales that are happening these days are for the best Class A assets in the strongest markets, said Fasulo.

With so much uncertainty about the economy, the smart money is sitting on the sidelines, waiting for signs of a recovery. “Investors are worried about trying to catch a falling knife,” said Fasulo. “You’ll see the market trickle back early next year, but I’m less optimistic that a flood will come back early next year.”

There are positive signs indicating that the sun won’t always refuse to shine. First, most apartment markets, especially on the coasts, are still undersupplied. The balance between supply and demand of units is expected to remain healthy through 2009. And there’s a reservoir of equity waiting on the sidelines, ready to pounce once the market begins to recover, indicating that when the market does pick up, it will pick up in a hurry.