A lump sum investment means investing the entire available amount in a mutual fund at one point in time, rather than spreading it out over months or years through SIP.
When lump sum is advantageous
1. After a major market correction (30%+ fall) — buying at a discounted price
2. When you receive a windfall (bonus, inheritance, property sale proceeds)
3. For debt/liquid funds where volatility is low and compounding benefits immediate investment
4. When market valuations are clearly below historical averages (P/E < 18 for Nifty)
Lump sum vs SIP in equity markets
**Hybrid approach**: Many experienced investors use lump sum strategically — maintaining SIPs as the base, and adding lump sum investments during significant market corrections (10–20%+ drawdowns).
**Mathematical comparison** for ₹1,20,000:
Lump sum wins here assuming linear 12% growth. In volatile markets, SIP's rupee cost averaging often closes or reverses this gap.
**Practical recommendation**: For regular salary income, SIP is the practical default. Invest lump sum from bonuses, incentives, or other windfalls — especially during market downturns.