MUMBAI, July 17: Foreign portfolio investment in the Housing Development Finance Corporation (HDFC) has increased to 30 per cent, the new ceiling approved by the Reserve Bank of India (RBI) to the company recently.From the earlier ceiling of 24 per cent, the participation by foreign institutional investors, non-resident Indians and overseas corporate bodies in the paid-up equity capital of HDFC has reached the 30 per cent ceiling.Accordingly, the RBI today warned the stock exchanges not to facilitate any further purchases of shares by these catagories of investors in the company, an RBI release said.As a result of the RBI announcement, HDFC shares came under selling pressure on the Bombay Stock Exchange. The scrip which opened at Rs 4700 eased to Rs 4255 at the fag end of session.Other companies like Infosys and Mastek have allowed FIIs to buy up to 30 per cent of the equity.