HSBC is the latest bank to shut down the Gupta family and business's accounts, according to Bloomberg, as reported by Business Day.
The bank has reportedly announced a wide-ranging investigation into any possible suspicious transactions relating to the family and its businesses, using external investigators.
The Guptas' accounts have already been closed by Nedbank, Absa, Standard Bank and FNB. In October, the family was granted a temporary reprieve when the High Court granted an interim interdict against attempts by the Bank of Baroda to close their accounts.
According to Bloomberg's sources, the Guptas' accounts were first closed by HSBC in 2014 after transactions that did not look like legitimate business were identified.
On Monday, HSBC told Bloomberg that any exposure the bank had to the Guptas' companies was "inadvertent", adding that for the last few years, "we have been in the process of identifying what there is and shutting it down".
The bank claimed that it was not in the same boat as a host of other firms that are linked to the Guptas.
"HSBC is in an entirely different position from some of the other companies which were intentionally seeking to do business with the Guptas and the Guptas' companies. HSBC was never interested in doing business with the Guptas' companies," the bank said.
In November, Lord Peter Hain, a former anti-apartheid campaigner who is now a member of the House of Lords in the UK, said he had asked the UK authorities to investigate HSBC, Standard Chartered and the Bank of Baroda for being the conduits of the Gupta's allegedly corrupt transactions.
According to Times Live, Dubai's central bank is also investigating Gupta transactions.
Last week, Daily Maverick reported that, according to Hain, HSBC South Africa had alerted its head office in London that suspicious transactions were taking place in the Guptas' accounts in Dubai and Hong Kong.
These transactions related to alleged money-laundering of alleged bribes related to a Transnet locomotive contract. The kickback was valued at R5-billion over two years.
Writing to Britain's Financial Conduct Authority, Hain reportedly said: "The records show how the Guptas would then split the money into multiple accounts in a typical money laundering fashion through multiple transfers. Also, money was transferred to HSBC accounts in Dubai... An important part of this is that HSBC SA staff had visibility of the Hong Kong accounts and warned London this was theft and money-laundering. However, London HSBC ignored that warning, presumably deliberately, and so no action was taken to prevent this illegal banking activity."
HSBC did not respond to Daily Maverick's questions.
Two weeks ago, The Guardian reported that HSBC had closed front companies linked to the Guptas. This reportedly occurred in 2014, in the same year that Standard Chartered closed accounts linked to the Guptas.
Standard Chartered has also been identified by Hain as having been a conduit for dodgy transactions.
Hain reportedly said: "This demonstrates yet again that any global company doing any business with the Guptas or Zumas is guaranteed to be badly contaminated."