Barclays Investment Bank (formerly known as Barclays Capital ) is the investment banking division of the British multinational Barclays , and is headquartered in London . It provides advisory, financing and risk management services to large companies, institutions and government clients. It is a primary dealer in U.S. Treasury securities and various European Government bonds .
Barclays Investment Bank has offices in over 29 countries and since the acquisition of Lehman Brothers ' main U.S. division in September 2008, employs over 20,000 people, with over 7,000 people working in the IT division.  This has significantly increased Barclays' presence in North America. 
Barclays' first investment banking arm was established in 1985 under the name Barclays de Zoete Wedd (BZW) in response to the Big bang in UK financial services. It was formed through the merger of Barclays Merchant Bank with a UK stockbroker de Zoete & Bevan and one of the London jobbing firms Wedd Durlacher. The equity and Corporate Finance Divisions were sold to Credit Suisse First Boston in 1998 with the remaining businesses dominated by Fixed Income and Structured Capital Markets being retained by Barclays and rebranded Barclays Capital (BarCap). 
Bob Diamond took charge of Barclays investment banking business in 1996. Diamond led the effort to purchase key assets of Lehman Brothers after its bankruptcy in September 2008, giving Barclays a key and instant foothold in investment banking.
In mid-March 2012, the trading name of Barclays Capital was changed to simply 'Barclays', and the name of the division was changed to 'Barclays Investment Bank'.