The Northern California Chapter of SIOR is made up of more than 150 of the very best brokers in markets, which include the Sa ... n Joaquin Valley, the Greater East Bay, Silicon Valley, Sonoma County, the Sacramento Valley, Marin County, Reno and San Francisco. SIOR brokers are a significant influence in the sales and leasing of commercial properties in all of these markets and represent the highest degree of professional integrity and ethics. read more