To achieve stable profits in event contract trading, the following conditions must be met:
### 1. Minimum Winning Rate Requirement
When the winning rate \( p > \frac{5}{9} \approx 55.56\% \), the expected profit is positive. The calculation is as follows:
\[
\text{Expected Profit} = f \cdot (1.8p - 1) > 0 \implies p > \frac{1}{1.8} \approx 55.56\%.
\]
### 2. Optimal Position Ratio (Kelly Formula)
According to the Kelly formula, the optimal position ratio \( f \) is:
\[
f = \frac{1.8p - 1}{0.8}.
\]
This formula ensures the maximization of capital growth rate in long-term trading, avoiding bankruptcy risk.
### Example Calculation
- **When the winning rate \( p = 60\% \)**:
\[
f = \frac{1.8 \times 0.6 - 1}{0.8} = 10\%.
\]
- **When the winning rate \( p = 70\% \)**:
\[
f = \frac{1.8 \times 0.7 - 1}{0.8} = 32.5\%.
\]
### Conclusion
- **Entry Condition**: The winning rate must exceed **55.56%**.
- **Position Strategy**: The position ratio for each investment is \(\frac{1.8p - 1}{0.8}\), dynamically adjusted based on the actual winning rate.
By strictly following this strategy, stable profits can be ensured in long-term trading while effectively managing risks.
