Why did Facebook just buy WhatsApp for $16 billion? Probably because if it didn’t, Google would have picked up the popular mobile messaging app for $10 billion. Two unnamed sources tell Fortune that Google reportedly made a $10 billion offer to buy WhatsApp that was apparently turned down in favor of Facebook’s much larger offer. In addition to offering less cash, Google also reportedly didn’t offer WhatsApp CEO Jan Koum a seat on its board of directors as Facebook did.

Adding to the Google-WhatsApp intrigue, The Information is reporting that Google last year actually offered to pay WhatsApp money if it agreed to tell Google that it was entering into acquisition talks with another party. This particular offer was worth a mere “millions” of dollars so it was obviously separate from Google’s later reported attempt to buy WhatsApp outright. The Information says that WhatsApp ended up rejecting this offer so it looks like Google was really in the dark when it came to knowing what companies were moving in on WhatsApp.

In explaining its decision to buy WhatsApp on Wednesday, Facebook CEO Mark Zuckerberg said that WhatsApp now has 450 million regular monthly users and added that it “is on a path to connect 1 billion people.” WhatsApp is particular popular in many key emerging markets, which means it could help Facebook extend its reach even further than where it already is.