How do billion-dollar deals get made in Silicon Valley? In the case of Facebook's acquisition of Instagram, the negotiation period was a mere weekend at Mark Zuckerberg's house, where he and Kevin Systrom, Instagram's cofounder and CEO, thrashed out a mutually agreeable valuation for the photo-sharing service. This is according to a Wall Street Journal report, which goes on to say that Zuckerberg informed Facebook's board of directors that he intended to spend $1 billion on Instagram on Sunday morning, April 8th, approximately 24 hours before the takeover became official. The board reportedly did vote on whether to approve the decision, but sources close to these proceedings describe them as "largely symbolic."

Facebook's COO, Sheryl Sandberg, is said to have been informed on Thursday of that week that Zuckerberg was going to aggressively pursue the purchase of Instagram, though she herself isn't reported to have participated in the meetings with Systrom. Amin Zoufonoun, Facebook's Director of Corporate Development — who, like Sandberg, joined the company after a previous stint at Google — was present during the negotiations, so at least some part of Zuckerberg's corporate team was there to assist him. Ultimately, however, the Facebook founder and CEO remains very much in control of the social juggernaut he started back in 2004. For more on the full timeline of Zuckerberg and Systrom's weekend talks, read the full WSJ report at the source link below.