The Reserve Bank of India (RBI) has tightened investment norms for residuary non-banking companies (RNBCS) to impart liquidity and enhance protection of depositors. The directed investments by RNBCS would be raised from the existing 80 pc of aggregate liabilities to depositors to 90 pc from April 1, 2005, an RBI release said on Tuesday. RNBCS would have to park 100 pc of depositors’ liabilities into directed investments from April 1, 2004, it said, adding the new norms for the directed credit would be effective from July 1, 2004. (PTI)