The amount of tech workers buying up housing is also up for debate. Though this article focuses on cash transactions (perhaps mortgaged ones don't contain occupational data?), it paints a picture of other white collar professions performing the majority of cash purchases of housing in the Bay Area.
The data was taken from a company that controls 10% of the real estate market in the Bay Area.
http://realestateconsulting.com/tech-buyers-only-a-small-por...