While investors acquired several desirable Ventura County commercial properties in the third quarter, vacancy rates in the office and industrial markets rose slightly from the previous three months.

Countywide office vacancies hit 9.3 percent, up from 8.6 percent in April-June period, according to data compiled by the Ventura office of CB Richard Ellis Group Inc. Available industrial space increased slightly in the quarter, with the vacancy rate rising two-tenths of a point, to 9.7 percent.

Even so, the 100-acre Conejo Spectrum Business Park in Thousand Oaks was bustling with activity during the quarter, when at least five properties changed hands.

The park, developed from a former Northrop Grumman Corp. campus acquired in 1998, originally was marketed to tech-biotech companies but later fell victim to the industry downturn. However, activity has since picked up.

Palisades Associates, a Santa Monica real estate investment group, paid $34 million in August for two substantially leased industrial buildings on Lawrence Drive totaling nearly 500,000 square feet. Conejo Spectrum Building Associates, the original developer of the park, sold its last two buildings on Rancho Conejo Boulevard for more than $15 million to Fowler Property Acquisitions LLC of San Francisco.

And in September, a new 36,000-square-foot industrial building developed by the Panatonni Development Co. was sold for $3.3 million to the Zaken Corp., a wholesaler/liquidator moving from Chatsworth. The company finds and sells surplus merchandise to eBay, flea markets and retail stores.

Oxnard’s MacInnes Ranch industrial park saw significant investor interest in the quarter as well. The local Lyle Family Trust paid $11.1 million to acquire a fully occupied industrial facility on Del Norte Street of more than 125,000 square feet, according to Tony Principe, president of Westcord Commercial Real Estate Services. The tenant is Berner Food Service, a restaurant supply company.

Colliers Seeley’s Oxnard office oversaw two additional investor deals at the park in September that received multiple offers, according to senior vice president John Ochoa. Oxnard-based Foxborough Park Inc. purchased a nearly 60,000-square-foot unoccupied building on Sturgis Road for near its $5 million asking price. Double E Investment LLC bought a building of more than 42,000 square feet on Jupiter Court for near its $3.9 million asking price.

“It’s still a buy market out there on the industrial side and I don’t think that will change until (interest) rates get to 8 percent,” said Mike Tingus of Lee & Associates’ Sherman Oaks office.

Meanwhile, the lease rate differential between the eastern and western parts of the county remained. Class-A office space was leasing for $2.20 to $2.25 a square foot in the East County on a full-service gross basis, compared with $2.10 to $2.15 in the West County.

Industrial space also was cheaper in the west, at 55 cents a square foot compared with 70 cents in the east, where very few vacant buildings are still available.

Among the larger lease deals in the quarter was one involving In-Three Inc., a 3D movie post-production company. In-Three signed a 10-year lease valued at $12 million for 36,000 square feet on East Thousand Oaks Boulevard in Westlake Village.

The year’s largest office deal to date in western Ventura County closed in September when Kush Games signed a five-year lease for nearly 20,000 square feet on Camino Ruiz in Camarillo.

Kush, a video game designer acquired by Take2 Interactive in January, is moving up from a 7,500-square-foot office it now leases elsewhere in Camarillo.

GE Fanuc Automation, which makes industrial automation software and systems, signed a lease agreement for 30,800 square feet of industrial space on Flynn Road in Camarillo. GE Fanuc, which is relocating its Central Coast operation from a smaller Ventura facility, is a joint venture between General Electric Co. and Fanuc Ltd. of Japan.