Facebook closed its acquisition deal with WhatsApp on Monday for $22 billion, an amount higher than the $19 billion previously reported.

The controversial acquisition of the messaging app sparked debate since February this year when the social networking giant detailed in a SEC filing that it plans to acquire WhatsApp for $19 billion in combination of $4 billion cash and stocks. The purchase amount is 19 times bigger than the amount Facebook doled out for the photo-sharing app Instagram, which only amounted to $1 billion.

A couple of privacy advocate groups urged the U.S. Federal Trade Commission (FTC) to investigate the acquisition deal, as it might be an unfair trade, which concerns the users' privacy. The app processes about 27 billion messages and 400 million photos per day, and has more than 600 million active monthly subscribers.

WhatsApp CEO Jan Kourn quickly dismissed this speculation and reassured users that it will not be like Facebook when it comes to privacy. WhatsApp doesn't collect and store data of users' search activities, GPS location, names, addresses and email addresses, and it will remain even after the acquisition.

"We are forming a partnership that would allow us to continue operating independently and autonomously. Our fundamental values and beliefs will not change. Our principles will not change. Everything that has made WhatsApp the leader in personal messaging will still be in place," Kourn wrote in a blog post.

Kourn will receive about $2 billion in stock for the next four years for him to stay with the company; he will remain CEO and a Facebook director, according to Reuters. WhatsApp's 70 employees will remain in its Mountain View, California headquarters and will work as a separate entity from Facebook.

The Facebook-WhatsApp acquisition deal was not a smooth journey. It had to go through the approval of the FTC that was granted in April and the European Commission that gave its blessing three days ago, after ruling out that the purchase will not hurt competition.