Unlike SIP, Public Provident Fund (PPF) has a lock-in period of 15 years. One of the few instruments to enjoy the exempt-exempt-exempt status, PPF offers tax deductions on investments up to Rs 1.5 lakhs per year. In addition, PPF currently earns an interest of 7.1%. SIPs, on the other hand, are market-linked and, therefore riskier than PPFs. However, the money you invest in SIPs is not locked-in for an extensive period. Therefore, SIPs provide higher liquidity compared to PPFs.