Messaging app provider Telegram says it has raised $850 million in the first part of its controversial initial coin offering (ICO), public records show.

If confirmed, the raise is by far the largest seen for any ICO to date. According to CoinDesk's ICO Tracker, the previous record was the token sale by Tezos, which raised $232 million last year. Filecoin and Bancor raised more than $200 million and $150 million in the same year, respectively.

The amount raised was revealed in an SEC notice of securities exemption, which also indicates that the firm aims to use the funds for "the development of the TON Blockchain, the development and maintenance of Telegram Messenger and the other purposes described in the offering materials."

Launched in 2013 by Russian brothers Pavel and Nikolai Durov, Telegram announced in January that it intended to raise $1.2 billion via a sale of its own token known as "grams." Having struggled with high operating costs, as previously reported by CoinDesk, a successful ICO would likely secure the struggling firm's future.

Part of the ICO is also aimed to open new avenues for the firm, financing development of a network for low-cost real-time payments and, later, a platform for decentralized identity, storage and more

It's so far unclear if the $850 million represents the token pre-sale, but that would appear likely. It further indicates that Telegram has had no problem appealing to VC firms and hedge funds in its capital-raising efforts.

The ICO is not without its critics, however, and cryptographic experts have questioned Telegram's security in the past. Additionally, there are concerns about the governance of the tokens, as detailed in the ICO white paper, and the voting power of the TON Foundation set up to manage the reserve tokens kept by Telegram.

MIT professor Christian Catalini previously told CoinDesk that the company should clarify details of its plans, adding that:

Telegram app image via Shutterstock