问题如下：
The risk management group estimates the 1-day 99% VaR on a long-only, large-cap equity portfolio using a variety of approaches. A daily risk report shows the following information:
1-day 99% VaR Estimates (by approach):
• Delta-Normal VaR: USD 441,940
• Monte Carlo Simulation VaR: USD 473,906
• Historical Simulation VaR: 495,584
Which of the following is the most likely explanation for the variation in VaR estimates?
选项：
A.Data problems
Differences in model assumptions
C.Endogenous model risk
D.Programming errors
解释：
Explanation: VaR measures will vary according to the
approach (delta-normal, historical simulation, Monte Carlo simulation). The
variation in these values does not suggest bigger problems with data or
programming/implementation nor is there any reason to suspect endogenous model
risk (e.g., traders gaming the system to lower risk values).
能不能举个例子什么是内生性的模型风险？
