With an aim to safeguard mutual fund investors from high-risk assets, regulator Sebi wants fund houses to shift all their investments to listed or to-be-listed equity and debt securities in a phased manner and reduce their exposure to unrated debt instruments from 25 per cent to only 5 per cent. Exposure to risky debt securities has emerged as a major risk for the capital market investors, including those coming through the mutual fund space, and the regulator has been making efforts to enhance its regulatory safety net against such risks. Taking forward certain decisions approved by Sebi's board earlier in June, the regulator has now finalised the draft amendments to the prudential norms for mutual fund schemes for investment in debt and money market instruments. Besides, some further amendments have been proposed for approval of Sebi's board at its next meeting later this month, officials said. A key fresh proposal is to reduce the existing overall limit for investment