The investment banking business provides advisory, financing and risk management services to large companies, institutions and government clients.

[12] Barclays traces its origins back to 17 November 1690, when John Freame, a Quaker, and Thomas Gould, started trading as goldsmith bankers in Lombard Street, London.

[15] David Barclay of Youngsbury (1729–1809), on the other hand, was a noted abolitionist, and Verene Shepherd, the Jamaican historian of diaspora studies, singles out the case of how he chose to free his slaves in that colony.

[46] Barclays, along with seven French banks, was named in a lawsuit filed in New York on behalf of Jews who were unable to reclaim money they deposited during the Nazi era.

[48] The most controversial of a set of loans provided by Barclays was the £30 million it gave to help sustain land reforms that saw Mugabe seize white-owned farmland and drive more than 100,000 black workers from their homes.

[55] On 31 October 2001, Barclays and CIBC agreed to combine their Caribbean operations to establish a joint venture company known as FirstCaribbean International Bank (FCIB).

Also in 2005 Barclays sealed a £2.6bn takeover of Absa Group Limited, South Africa's largest retail bank, acquiring a 54% stake on 27 July 2005.

[63] Barclays also exited retail-banking operations in the Caribbean-region which extended as far back as 1837 through selling of its joint venture stake in FirstCaribbean International Bank (FCIB) to CIBC for between $989 million and $1.08 billion.

[70] That year also saw Barclays Personal Investment Management announcing the closure of their operation in Peterborough and its re-siting to Glasgow, laying off nearly 900 members of staff.

[82][83] On 12 June 2009, Barclays sold its Global Investors unit, which included its exchange-traded fund business, iShares, to BlackRock for US$13.5 billion.

[89] In March 2009, Barclays obtained an injunction against The Guardian requiring it to remove from its website confidential leaked documents describing how SCM, Barclays' structured capital markets division, planned to use more than £11 billion of loans to create hundreds of millions of pounds of tax benefits, via "an elaborate circuit of Cayman Islands companies, US partnerships and Luxembourg subsidiaries".

[90] In an editorial on the issue, The Guardian pointed out that, due to the mismatch of resources, tax-collectors (HMRC) now have to rely on websites such as WikiLeaks to obtain such documents.

[97] On 16 September 2008, Barclays announced its agreement to purchase, subject to regulatory approval, the investment-banking and trading divisions of Lehman Brothers (including its former headquarters at 745 Seventh Avenue) which was a United States financial conglomerate that had filed for bankruptcy.

[104] In September 2014, Barclays was ordered to pay $15 million in settlement charges that alleged the bank had failed to maintain an adequate internal compliance system after its acquisition of Lehman Brothers during the 2008 financial crisis.

[82][107] Existing Barclays shareholders complained they were not offered full pre-emption rights in this round of capital raising, even threatening to revolt at the extraordinary meeting.

[114] In July 2012, Barclays revealed that the FSA was investigating[114] whether the bank adequately disclosed fees paid to Qatar Investment Authority.

The Financial Services Authority announced an expansion of the investigation into the Barclays-Qatar deal in January 2013, focusing on the disclosure surrounding the ownership of the securities in the bank.

[119] The FSA's director of enforcement described Barclays' behaviour as "completely unacceptable", adding "Libor is an incredibly important benchmark reference rate, and it is relied on for many, many hundreds of thousands of contracts all over the world.

[129] In June 2014, the US state of New York filed a lawsuit against the bank alleging it defrauded and deceived investors with inaccurate marketing material about its unregulated trading system known as a dark pool.

[132] To ward off the effects of Brexit Barclays borrowed £6 billion from the Bank of England between April and June 2017, as part of a post-referendum stimulus package launched in August 2016.

[138] In June 2017, following a five-year investigation by the UK's Serious Fraud Office covering Barclays' activities during the financial crisis of 2007–2008, former CEO John Varley and three former colleagues, Roger Jenkins, Thomas Kalaris and Richard Boath, were charged with conspiracy to commit fraud and the provision of unlawful financial assistance in connection with capital raising.

[141] In February 2018, the Serious Fraud Office charged Barclays with "unlawful financial assistance" related to billions of pounds raised from the Qatar deal.

The company sued the bank in a £1.5 billion lawsuit, claiming that it had "deliberately misled" the market over the terms of its capital raising deal with Qatar.

[143] However, during the hearing in the High Court of London, the Barclays lawyer, Jeffery Onions accused Staveley of "significantly exaggerating" her business relationship with the Abu Dhabi sheikh and of creating a "hustle" by getting involved in a crucial capital raising.

[145] In February 2020, it was reported that, in a pilot programme at its London headquarters, the company used tracking software to assess how long employees spent at their desks and warn them if they took excessive breaks.

[148] On 31 October 2021, in a surprise move, group CEO Jes Staley agreed to step down amid investigation of his ties to the sex offender Jeffrey Epstein.

[156][157] In early February 2025, Barclays experienced a significant IT glitch that disrupted online and mobile banking services for several days.

[158] In February 2025, The bank set aside £90 million to address potential compensation claims related to a car finance mis-selling scandal.

[159] In 2017, Barclays faced protests by environmentalists because of its ownership of Third Energy Onshore which planned to extract natural gas using hydraulic fracturing (fracking) at Kirby Misperton in Yorkshire.

[160][161] In 2020, the campaign group ShareAction filed a resolution at Barclays AGM[162] because of its role as Europe's largest funder of fossil fuel companies.