Secure messaging company Telegram raised $850 million in the pre-sale stage of an initial coin offering (ICO) to develop and maintain its messaging apps, and also to work on its blockchain technology.

The funds were raised from a private sale of tokens to investors at a discount of more than 50 per cent, with a $1.15 billion public ICO expected to follow in March. The ICO will be the largest to date, with the pre-sale figure alone topping all other such offerings held so far.

Bloomberg reported in January the pre-sale would likely exceed the $600 million Telegram originally aimed to raise, as demand pushed the total up. The news site also stated participants will need to hold on to their coins for a lock-up period of up to 18 months following the ICO.

The sale represents the first outside investment in the company, which so far was funded by CEO Pavel Durov (pictured) and his older brother Nikolai. An ICO is used to raise funds for a cryptocurrency venture, which can be used as a source of capital by start-ups.

Telegram is now aiming to develop payment services alongside its messaging apps, including micropayments and peer-to-peer transactions.

In January, the company launched an experimental app for Android and iOS which it touted as being faster and more power efficient than the original.

Apple recently blocked Telegram temporarily after it was alerted “illegal content, specifically child pornography” was shared on the messaging app.