From the Mercury News: Silicon Valley office vacancies near 20 percent

Nearly one-fifth of Silicon Valley office space stood empty last quarter, while landlords lowered rents to try to retain tenants and attract new ones, according to a [report from commercial real estate firm Grubb & Ellis] released Friday.

...

The rising vacancy rate is "re-emphasizing that this is the slowest commercial real estate market the valley has seen since the dot-com bust in 2001," the report stated.



Empty space for research and development, the one- to three-story buildings where so many smaller tech companies reside, is also beginning to pile up, said Dick Scott, Grubb & Ellis' managing director in Silicon Valley. ...



"There was a temporary period of time where we all were naively optimistic that R&D would hold up. But it's taking a hit now," he said.

...

Said the Grubb & Ellis report: "Expect asking rents to decrease as companies put unoccupied space onto the market."

Some of the increase in the vacancy rate was because of new office space coming online, but it sounds like Grubb & Ellis expects a significant amount of sublease space to come on the market too. That is usually a bad sign for rents - and also suggests companies don't expect much growth.