Fintech Tingo's share have slumped more than halve on Tuesday after short seller Hindenburg Research said it had placed a bet against the Nasdaq-listed fintech group whose chief executive made a bid for Sheffield United football club.

Hindenburg alleged in a report released on Tuesday that the company, which operates a mobile technology and payments business focused on farming and food-processing operations in Nigeria, was an “exceptionally obvious scam”.

He claimed that Tingo had lied about some of its partnerships and products, did not hold the mobile licence it required to operate parts of its business and said it found no evidence that the group owned a food-processing facility nor that it had started to build one.

It also highlighted a number of what it called “red flags” in the company’s accounts, including the presence of several errors and typos in its financial statements.

Tingo, which had a market capitalisation of more than $400mn before the report was released, declined to comment. Its shares fell as much as 60 per cent on Tuesday.

Tingo’s business rests on claims that it has distributed 9mn branded mobile devices to Nigerian farmers through which they can access cheap credit and microloans — as well as weather forecasts, prices of farm input and produce — on the company’s online marketplace, Nwassa.

Nwassa generated $125mn in revenue last quarter, or about 15 per cent of Tingo’s total revenue, according to the report. However, the platform’s website has been under maintenance for months and Hindenburg questioned the existence of the majority of the 9m users.

Questions over Tingo’s business have mounted in recent months after the chief executive of the holding company, Dozy Mmobuosi, submitted a bid in February for Sheffield United.

The Athletic sports website in February alleged that an airline that Mmobuosi had advertised, and which he registered in England as Tingo Airlines Limited, appeared to not exist.

Tingo did not address the Athletic’s allegation directly but has previously said it was being targeted by short sellers and was investigating the matter.

Big Four auditor Deloitte is also in the short seller’s crosshairs after its Israeli arm gave Tingo a clean, unqualified audit, leading Hindenburg to suggest they had “missed or rushed through procedures that would have uncovered important findings”.

The chief executive of Deloitte Israel, Ilan Birnfeld, said the firm would not comment on a client.

The Financial Times recently visited Tingo’s sparsely staffed headquarters in Lagos, where the company’s Nigeria CEO and his chief technology officer struggled to answer basic questions, including on the identity of their banking partner.

After a press release from Tingo late last month announcing a “multi-billion-dollar pipeline” of commodities exports going through Dubai, the FT visited its Dubai branch, located in the Jumeirah Lake Towers, which houses the Dubai Multi Commodities Centre free zone. The office was empty. One neighbour said a few people occasionally came into the premises, but had not been seen for several days.