Messaging app Telegram has raised an additional $850 million for its initial coin offering, according to documents filed with the SEC on Thursday. The funding means that Telegram has raised a total of $1.7 billion so far for what will likely be the largest ICO in history.

Telegram last raised $850 million in February for its first round of funding. Rather than issue traditional company shares, Telegram is giving investors discounted rates for its “Gram” virtual coins, which will be used to build a decentralized network for the Telegram app.

While investors were required to cut multi-million dollar checks to buy heavily discounted Telegram coins for the app's first round of funding, this second $850 million round required a minimum investment of $1 million, Telegram told the SEC.

Dubai-based Telegram is reportedly planning to raise yet another $850 million in a third offering to investors, bringing its grand total of funding to roughly $2.5 billion. Telegram planned to sell its Grams in a public presale as well but abandoned the plan after the SEC increased its scrutiny of the ICO market, according to a person familiar with the matter. The app recently [announced] ( that it has 200 million monthly users.

Reporting by Alex Heath.