Indian-origin Murthy became a majority shareholder in the investment company -- founded by the couple in 2013 -- after Sunak stepped down as its director in 2015 when he became an MP.

In a letter to Deputy Prime Minister Oliver Dowden, the Labour Party has asked what impact the closure of Catamaran Ventures could have on the government-backed business and any other companies it retained a stake in, the BBC reported.

The party's national campaign co-ordinator Pat McFadden also asked what the arrangement was for the payment of tax owed to HMRC (His Majesty's Revenue and Customs), and whether the firm would fulfil all its liabilities to the British taxpayer.

"It is vital that these questions are answered in the interests of, to quote the Prime Minister himself, 'integrity, professionalism and accountability'," McFadden wrote in the letter.

It was reported last year in the local media that Catamaran Ventures held shares in Study Hall -- an education start-up which received a government grant of almost 350,000 pounds.

According to the BBC, with the election expected in 2024, McFadden's move most likely signifies Labour's willingness to try to make Akshata and her wealth an issue in campaigning.

Denying that the Labour was trying to create "political capital" out of the issue, McFadden said his party just wanted to ensure that "everything is properly declared here, as this venture now winds up".

A spokesperson for Murthy said after the business was wound up, "a significant donation has been made to ShareGift, an independent UK-registered charity with experience accepting donations in the form of shares".

With the exception of one company, all the holdings of Catamaran Ventures have been transferred to ShareGift, the BBC reported.

Early last year, Sunak came under scrutiny after it emerged that his billionaire wife had shares in a childcare agency, which stood to gain from a new policy announced in the then budget.

It was reported that Koru Kids, which listed Murthy as a shareholder, was likely to benefit from a scheme announced by Chancellor Jeremy Hunt.

According to an October 2023 media report, Murthy earned more than the combined parliamentary salaries of all Labour MPs in the year.

The couple entered The Sunday Times Rich List in 2022 for the first time with their joint 730 million pound fortune.

Akshata Murthy is said to be wealthier than even King Charles III due to her 430 million pounds stake in her billionaire tycoon father Narayana Murthy's IT empire.