Sources tell Digital Trends that Google (NASDAQ:GOOG) is negotiating the purchase of messaging app WhatsApp.

Talks between the Internet search giant and the start-up have been on going for at least a month. WhatsApp’s management is said to be pushing for an acquisition price of almost $1 billion.

WhatsApp is said to have annual revenue of about $100 million. The app, which operates in 100 countries, processed 18 billion messages on New Year’s Eve alone. Users pay 99 cents a year to use the service.

The deal with give Google a flashy messaging service, filling a missing link it the company’s mobile communications platform, without having to develop and brand its own service.

Last year, Google paid $1 billion to purchase photo-sharing app Instagram.

Shares of Google fell more than 1% in Monday morning trading.