JPMorgan, Goldman Sachs, Bank of America Merrill Lynch and Morgan Stanley, as well as Britain's Asia-focused Standard Chartered said they would try to support London's financial sector
A leave vote means the future of Britain's financial services industry is now hanging in the balance.
Standard Chartered said it will stop providing financing to parts of the diamond and jewellery industries as part of a review of its exposure to risky sectors.
Many of the jobs will now be offshored to lower income countries such as India, China and Poland
This is part of an 'aggressive and decisive set of action' to shore up the company.
The job cuts will affect almost a fifth of the bank's workforce.
As part of a cost-cutting plan, the bank is now dismantling its stock broking, equity research, and equity listing desks worldwide.
The total number of staff to be cut has not been finalised but could be as high as 90 people, the sources said, declining to be identified because the matter is confidential.