A company called Flannery Associates has been buying large plots of land in a largely agricultural region 60 miles northeast of San Francisco. The company, which has little information public about its operations, has committed more than $800 million to secure thousands of acres of farmland, court documents show. One parcel after another, Flannery made offers to every landowner for miles, paying several times the market rate, whether the land had been listed for sale or not. Flannery is the brainchild of Jan Sramek, 36, a former Goldman Sachs trader who has quietly courted some of the tech industry’s biggest names as investors. They include Mr. Moritz; Reid Hoffman, the LinkedIn co-founder, venture capitalist and Democratic donor; Marc Andreessen and Chris Dixon, investors at the Andreessen Horowitz venture capital firm; Patrick and John Collison, the sibling co-founders of the payments company Stripe; Laurene Powell Jobs, founder of the Emerson Collective; and Nat Friedman and Daniel Gross, entrepreneurs turned investors. Andreessen Horowitz is also a backer. As Flannery began seeking property, it bought so much land, so fast, that it spooked locals who had no idea who the buyer was or the plans it had in mind. This week representatives for Flannery reached out to elected officials requesting meetings about their plans. The land that Flannery has been purchasing is not currently zoned for residential use.