Five years ago, Sheikh Mansour Bin Zayed al-Nahyan, of Abu Dhabi’s ruling family, swooped into London with other Middle Eastern investors as saviors of Barclays in an $11 billion deal that would rescue the beleaguered bank from government intervention.

Five years later, Sheikh Mansour has quietly cashed out, selling his 758.4 million shares through his investment vehicle  International Petroleum Investment Company on June 20, according to a Financial Times report Friday.

Barclays shares have gained more than 60 percent since the initial investment in October 2008, now valued at 288.10 pence ($4.39) each, putting the sheikh's shares at $3.35 billion.

Barclays was under pressure to increase its capital ratios and was eager to avoid asking the government for taxpayer help. With help from Middle Eastern sovereign wealth, they have been able to recover the bank's reputation.

At the time, the bank offered potential investors a 23 percent discount and warrants that could be converted into shares. Existing shareholders were outraged because they were not given the chance to participate in the capital increase. However, now the UK financial regulator is investigating the fees linked to the deal.