In fact, the number represents the lowest transaction volume since the second quarter of 2004, according to the Northbrook, IL-based company, which has been compiling data on the net lease marketplace since late 2003.

What's more, the decline during 2008 compounds what was already a large decline at the end of 2007. "I think everyone expected the number of deals getting done to be pretty low," Jeff Rothbart, Boulder principal and research director, tells GlobeSt.com. "Q4 '07 was not a pretty quarter either. But the deals closed in that quarter was down 73% from the previous quarter." Large declines two years in a row, he adds: "That's a big number."

The paucity of debt is in large part to blame for the steep decline in closed deals, says Boulder. "It is Boulder's position that the debt terms and lack of available financing have had a greater impact on the slowdown rather than asset pricing," its Q4 Net Lease Market Report states.

The spread between buyer and seller expectations is a significant factor as well, even if Boulder doesn't think it is the primary driver of the lack of transaction velocity. And this, too, boils down to the credit market, says Rothbart, since "buyers can't get financing" that makes transactions make sense today.

The bid-ask spread did narrow during the fourth quarter, according to Boulder's research, with cap rate increases in the industrial, office and retail net lease sectors. The biggest increase in mean cap rates, by 21 basis points, was in the office sector. Mean cap rates for net lease industrial assets increased by eight basis points and for net lease retail properties by one basis point.

Boulder's research also finds that a rising number of assets available for purchase are becoming increasingly stale. While the overall number of properties on the market rose from Q3 to Q4, a greater percentage of those are properties that are not trading but rather lingering on the market. That has combined with fewer new properties being put up for sale.

Looking at its data from Q4 2003 through Q3 2007, "historically on average 43% of all available assets were new to the marketplace over the previous quarter," the report states. "Since the recession began, however, that numbers has dropped to 35% and this quarter only 34% of the total assets available were new to the marketplace.

"When this lack of fresh assets being placed in the system is combined with the difficulties confronting the capital markets, it becomes apparent that the market remains saturated with old assets priced at valuations that do not pencil in today's real estate world. This stale inventory is not trading, resulting in a perception in the marketplace that nothing new is available for purchase."

As for what might be coming down the pike in 2009, rising commercial mortgage defaults could be a leading indicator of a new properties coming to market--but at pricing more realistic for today's market, says Rothbart. Upcoming CMBS loan expirations will be another factor, too, with owners having to ask themselves, "'Do I put more capital in or do I sell this thing?'"

"I think there's going to be another wave of properties coming to market," Rothbart concludes.