A whistleblower claims that the U.S. disregarded evidence that a major U.K. bank was aiding in the funding of sanctioned Iranian organizations.

• In 2012 and 2019, Standard Chartered, a London-based bank primarily serving clients in emerging markets, was fined more than $1.7 billion for violating sanctions on Iran and other blacklisted countries.
• The bank denies that it ran transactions for any organizations designated as terrorists.
• According to court filings by former Standard Chartered Bank (SCB) employee Julian Knight, U.S. officials lied when they denied that Knight had provided them with evidence of more significant wrongdoing by the bank.

Allegations in recent U.S. federal court filings claim that a major British bank provided financing to sanctioned Iranian entities and terrorist groups, with American authorities allegedly disregarding the relevant evidence.

In 2012 and 2019, Standard Chartered, a London-based bank primarily serving clients in emerging markets, was fined more than $1.7 billion for violating sanctions on Iran and other blacklisted countries.

The bank denies that it ran transactions for any organizations designated as terrorists.

According to court filings by former Standard Chartered Bank (SCB) employee Julian Knight, who turned whistleblower, U.S. officials lied when they denied receiving evidence of greater wrongdoing by the bank. Knight claims that the officials then dismissed his whistleblower case against the bank in 2019 in order to protect it. Knight has now filed a request to reinstate the case in a U.S. federal court in New York.

Knight, who led a Standard Chartered transaction services unit from 2009 to 2011, was one of two whistleblowers who provided U.S. investigators with confidential bank statements in 2012 and 2013. These statements, which document transactions that Knight claims contain evidence of further sanctions breaches, including violations beyond 2007, when the bank stated that it had stopped any dealings with Iran.

The Knight's court filing claims that the U.S. government engaged in a "massive fraud" by denying that he presented "compelling evidence" that Standard Chartered facilitated billions of dollars in banking transactions for Iran, terrorist groups, and their front companies, as reported by the International Consortium of Investigative Journalists.

The court filing reveals that some of the evidence pointed towards the bank's clients being front companies for Iran's Islamic Revolutionary Guard Corps, Hamas, Hezbollah, and Iran-linked entities in various countries, including the United Arab Emirates, Kuwait, Germany, and others.

In 2019, two whistleblowers claimed that U.S. authorities who investigated Standard Chartered made false statements to a court in order to dismiss their whistleblower's reward claim, according to the BBC.

The FBI agent and other authorities stated that the whistleblowers' allegations did not result in the discovery of any new violations. As a result, the case was deemed "meritless" by the court. CNBC has reached out to the U.S. Department of Justice for comment.

The ICIJ report states that Knight's latest claim claims that the U.S. government either lied about conducting a thorough investigation into his claims or was fully aware of the transactions he provided and intentionally concealed them, with the government's own statements supporting the latter scenario.

A spokesperson for Standard Chartered responded to a CNBC request for comment on Knight's court filing by stating that it is "another attempt to use fabricated claims against the bank, following previous unsuccessful attempts." The spokesperson also said that the "false allegations underpinning it have been thoroughly discredited by the U.S. authorities, who undertook a comprehensive investigation into the claims and said they were 'meritless' and did not show any violations of U.S. sanctions."