"We know that the company was valued at about $2 Billion in 2015" also looks familiar. You'll recall Mark's 2015 trade show interview. When asked his plans for the company he stated he hoped to sell it "For a couple Billion dollars". Now Microsoft just bought GitHub "just a web based hosting service" yesterday for $7.5 Billion.
Remember Microsoft settled with SFOR a couple years ago. Do you think they might bid a similar amount for SFOR? IMHO that figure is now in the realm of possibility. Know what you own!