Infrastructure Development Finance Co (IDFC) is looking to increase the proportion of foreign currency debt in its total loan portfolio, prompted by a burgeoning demand for financing in infrastructure. IDFC may raise forex loans to 12-13% of its total portfolio from 8% now depending on the interest rate environment. The company’s forex exposure is fully hedged.The infra finance firm is looking to raise Rs 5,000 crore through 10-year tax-saving bonds by March 2012. The bonds, which are secured in nature and rated ‘AAA’ by ICRA and Fitch Ratings, have a lock-in of five years after which they can be redeemed. The bonds offer 9% annualised return and have been launched in two series — one will pay interest on cumulative basis and another will pay interest on non-cumulative basis.