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Compounding & Regular Investing: The Science of the Snowball

Compound interest is the eighth wonder of the world. Four real scenarios show CNY 1,000/month over 30 years snowballing from CNY 360K contributed into CNY 1.5M.

The Compound Formula and the Power of Time

Future value: FV = PV × (1 + r/n)^(n×t) + PMT × [(1 + r/n)^(n×t) − 1] / (r/n)

CNY 100K principal, 10% p.a., 30 years:

  • Simple: 10 + 10 × 10% × 30 = CNY 400K
  • Compound: 10 × 1.1^30 = CNY 1.745M
  • A 4x+ gap

Regular Investing: The Steadiest Path for Ordinary People

SIP = a fixed monthly amount into the same fund, no market timing.

Key advantages:

  • Forced saving builds discipline
  • Averages your cost — dips buy more shares
  • No forecasting needed; long-run odds of profit are high

History: 10-year SIPs into the CSI 300 from any start date won ~85% of the time, at a median 8%–10% p.a.

4 Real Wealth-Planning Scenarios

1. Fresh graduate at 25: CNY 2,000/month to age 60 (35 years) at 8% → CNY 4.5M.

2. At 30: CNY 3,000/month, 25 years, 8% → CNY 2.84M.

3. At 35: CNY 5,000/month, 20 years, 8% → CNY 2.94M.

4. At 40: CNY 8,000/month, 15 years, 8% → CNY 2.71M.

Start earlier, invest less monthly, end up with more — time beats amount.

3 SIP Traps

Trap 1: waiting for a dip to start. The core of SIP is discipline — dips are exactly when you cheapen your average.

Trap 2: fund-hopping. Pick 3–5 funds of different styles and hold; don't churn on short-term noise.

Trap 3: treating SIPs as deposits. A SIP is an investment — use money you won't need for 3–5 years.

💡 Skip the math — try the GFWPS tool:Compound & Regular Investing

📌 FAQ

Which funds for a SIP?

Broad indices (CSI 300, CSI 500, S&P 500) plus actively managed funds with strong long-term records.

When to take profit?

Set a 50%–100% target and exit in tranches, or sell when the index breaks below its 200-day line.

What if my SIP is down?

Check the fund itself; if it's sound, keep the discipline and continue.