An investment of ₹200 per day in mutual funds for 12 years and 2 months can help a person build a ₹20 lakh corpus. The investment of ₹8.9 lakh will generate returns of over ₹11.3 lakh at an expected annual growth rate of 12%, as per NDTV Profit. Investors can use the 'step-up' technique to build a significantly larger corpus.