Durov wrote on his VKontakte page that he had sold 12 percent of the company to Ivan Tavrin, the general director of Russian telecoms giant Megafon and a member of the Mail.Ru Group board of directors.
In his post, Durov said that as a founder, he would continue to oversee the company's functioning, and the deal would not affect VKontakte management.
Russian business daily Vedomosti reported that sources close to VKontakte partners and shareholders said the deal was signed in December 2013. The amount of the sale is unknown.
Vedomosti's sources said the company is valued at $3 billion to $4 billion.
The move comes after other major reshuffling within the VKontakte top-management. Earlier this week, VKontakte announced that the company had replaced its vice president and chief financial officer with new team members.