Ideally, you should invest at least 25% of your portfolio in debt. This can be through FDs, PPFs, or debt funds. Since this part of your portfolio is your safety net, we usually advise clients to stick to the safer category of debt funds, i.e. Liquid funds. For portfolios smaller than Rs. 50 Lakhs can choose simple Fixed Deposits in Top 5 banks of India for this portion of the portfolio.