Nippon India Small Cap Fund has emerged as the top-performing small-cap scheme with strong SIP and lump-sum returns across 3 to 15 years. With assets of over Rs 68,000 crore and a focused strategy of investing in high-growth small-cap companies, the fund has rewarded long-term investors handsomely. However, it carries a Very High Risk rating, making it suitable only for investors with a long investment horizon and higher risk tolerance.