The Financial Conduct Authority is considering whether to investigate whether Citi breached financial transparency rules after the company was criticised for failing to publicly disclose how it calculated how much it paid out in tax and other fees.

In a report released last week, the FCA said it had been unable to obtain a full copy of Citi Corp’s 2013 annual report as it was “disclosed in redacted form”.

“It is important that any company that provides its financial information to a financial services provider be made available to the public in a manner that allows the public to obtain an accurate picture of the company’s financial position,” the FCO said.

“This requires the provision of a clear and transparent summary of the financial information, including the type of reporting required by the regulator, and the type and format of data used to calculate the company and the number of employees it employs.”

Citi declined to provide a copy of the annual report.

The regulator said it was concerned that the disclosure was “not clear or comprehensible”.

Citigroup’s 2013 tax return was not released as part of the FACA’s investigation because the company did not have a “fair and neutral” view of the amount it paid in tax, and “it did not provide clear and reasonable reasons for the discrepancy”.

The FCA’s investigation was not carried out in a way that would allow “reasonable” people to have a fair and impartial view of Citigroup, the regulator said.

Citi has been criticised by some for its accounting practices.

Its shares have fallen more than 40 per cent in the past year.

Cite data for Citi was provided by the company on Friday, which showed the value of the total assets of CITIGS fell by $4.5bn to $1.27 trillion in the year to the end of June.

As a result, the value for CITigroup was reduced by $5.6bn to just $9.7bn.

There were no changes to the value in the share purchase agreement between the two companies, which was the source of Cittagong’s criticism.

Analysts at investment bank Jefferies said it is likely the FCTA will investigate the company for breaching its accounting policies.

Jefferies’ financial analyst, Ben Daley, said the FTC’s “pivotal” focus should be on Citigong’s accounting.

However, he said the investigation could not be completed until the company released its full annual report to the regulator.

Daley said there was a “huge gap” between what was revealed in the report and what was actually disclosed.

This was particularly so because the information that was released in the redacted form “does not reflect CitiCorp’s business model or its operating philosophy”.

It was important that Citi comply with transparency requirements, Daley said.

“The FCTAs’ focus is not on the accounting practices of Citing but rather on how CITICOs accounting works,” he said.