Unilad, one of the biggest publishers on Facebook, has gone into administration, putting hundreds of jobs at risk and casting doubt on whether outlets that rely on the social media platform for distribution can become sustainable businesses.

The website’s parent company, Bentley Harrington, has debts of more than £6m, including £1.5m owed to HMRC, a court heard on Thursday.

Unilad’s co-founder Alex Partridge, who is owed £5m by the company after successfully arguing he was cut out of the business, had also called for it to be put into administration.

Unilad’s existing financial backer, Linton Capital, has offered the administrators £10m in cash “to acquire the substantial part of the business”, as part of a joint bid with the internet investment company RocketSports, according to documents seen by the Guardian.

Linton Capital said it had already held detailed discussions and drawn up a “list of the employees we would wish to keep”. It said its offer could be completed within 10 days and although it could involve downsizing parts of the company, all creditors would be paid in full and the “majority” of staff would stay with the business.

The £10m valuation is substantially below valuations that have previously been attached to Unilad and raises questions over the valuations of other online publishers. Other investors are also thought to be interested in the company.

Unilad declined to comment.

The company, which began life as a student “banter” page, is one of the world’s biggest publishers of viral content. It has hundreds of employees based at its headquarters in Manchester and has secondary offices in Shoreditch, London, and in New York.

Last month, the Guardian revealed HMRC representatives had issued a separate petition to liquidate Bentley Harrington, which was postponed after the company asked for more time.

On Thursday, the leading content on Unilad’s Facebook page included pictures of a crashed Ferrari, several videos of dogs and a story about a man falling from a train in India.

Its understanding of the sort of video content Facebook audiences want to watch enabled it to become the fourth-biggest publisher on the social network in August, according to data from the analytics company NewsWhip. Facebook recently said it would prioritise higher-quality news in users’ feeds.

Many viral publishers have struggled to translate their enormous reach into a profitable business model, owing to the high cost of making bespoke native ads. Sources in the advertising industry suggested many agencies had cut back their dealings with Unilad before Thursday.

Unilad’s co-chief executive Sam Bentley left the company in June after unspecific “allegations of historical misconduct” against it, with Unilad saying other staff had been disciplined as a result of an internal investigation.

Unilad shares a founder with LadBible but is now entirely separate from its fellow Manchester-based business, which is the biggest publisher worldwide on Facebook and has not reported any financial concerns.