The bank says the issue will allow it to strengthen its balance sheet as well as take advantage of new growth opportunities.
Barclays group chief executive John Varley says: “Through our capital raising today we strengthen our capital base and give ourselves additional resources to pursue our strategy of growth through earnings diversification.
“We position ourselves to capture opportunities for new business at attractive margins in our retail and commercial banking businesses and in investment banking and investment management.
“Our ability to capture the opportunities is reinforced by the new and strengthened relationships we have announced today.”
He adds: “We draw strength from the continued resilience of our trading performance, with profits in May well ahead of the monthly run rate of last year.”
Barclays will be maintaining its interim dividend at 11.5p – the level it paid last year.