学费增长预测计算器 — 公式
## How Endowment Spending Works
Endowments are designed to provide perpetual funding. The spending rate must be low enough that investment returns preserve the real (inflation-adjusted) value of the endowment.
### Formula
**Annual Spending = Endowment Value x Spending Rate**
**Sustainable if Spending Rate <= Expected Return - Inflation**
### Common Practice
- Most institutions spend 4-5% annually
- The "Yale Model" suggests 5.25% with a diversified portfolio
- Spending above the real return rate erodes the endowment over time
Endowments are designed to provide perpetual funding. The spending rate must be low enough that investment returns preserve the real (inflation-adjusted) value of the endowment.
### Formula
**Annual Spending = Endowment Value x Spending Rate**
**Sustainable if Spending Rate <= Expected Return - Inflation**
### Common Practice
- Most institutions spend 4-5% annually
- The "Yale Model" suggests 5.25% with a diversified portfolio
- Spending above the real return rate erodes the endowment over time
计算示例
A $50M endowment with 5% spending rate, 7% expected return, 3% inflation.
- Annual spending: $50M x 0.05 = $2,500,000
- Real return: 7% - 3% = 4%
- Spending (5%) > Real return (4%): Not sustainable long-term
- Net growth: $50M x (7 - 5 - 3)/100 = -$500,000 per year