Explanation

This question addresses two common biases in performance analysis:

Hedge Fund Analysis - Survivorship Bias

• When hedge funds stop trading (fail), they are removed from the database
• This creates survivorship bias - only successful funds remain in the database
• Survivorship bias overstates the performance of the surviving funds
• Since Sharpe ratio = (Return - Risk-free rate) / Volatility, overstated returns lead to overstated Sharpe ratios
• However, the question asks about the impact on average Sharpe ratio - removing failed funds (which typically have low or negative Sharpe ratios) actually understates the average Sharpe ratio because we're excluding the worst performers

Real Estate Fund Analysis - Liquidity Bias

• Improved liquidity and more frequent trading in real estate funds
• This reduces illiquidity premium that was previously embedded in returns
• As liquidity increases, the required return decreases (lower illiquidity premium)
• This leads to lower returns for the same level of risk
• Therefore, the Sharpe ratio decreases because numerator (return) decreases while denominator (volatility) may remain similar

Correct Answer Analysis

Option A correctly identifies:

• Hedge funds: Average Sharpe ratio is understated (because we're removing failed funds with poor Sharpe ratios)
• Real estate funds: Average Sharpe ratio has increased (contradicts the liquidity effect described above)

Wait - let me reconsider the real estate fund impact:

• Improved liquidity should decrease returns (lower illiquidity premium)
• This would decrease the Sharpe ratio, not increase it
• Therefore, Option A cannot be correct

Let me check the other options:

Option B:

• Hedge funds: Sharpe ratio overstated (incorrect - it's understated due to survivorship bias)
• Real estate funds: Sharpe ratio decreased (correct due to liquidity improvement)

Option C:

• Hedge funds: Volatility overstated (incorrect)
• Real estate funds: Volatility decreased (possible but not the primary impact)

Option D:

• Hedge funds: Volatility understated (possible due to survivorship bias)
• Real estate funds: Volatility increased (unlikely with improved liquidity)

Actually, let me reconsider the hedge fund impact more carefully:

• Survivorship bias means we only see funds that survived
• Failed funds typically have high volatility and poor returns
• By removing them, we're removing high-volatility observations
• This understates the true average volatility of hedge funds
• And since we're removing poor performers, we're overstating the average Sharpe ratio

Therefore, the correct impacts are:

• Hedge funds: Sharpe ratio overstated, Volatility understated
• Real estate funds: With improved liquidity, returns decrease (lower illiquidity premium), so Sharpe ratio decreases

Looking at the options, Option B correctly states:

• The average Sharpe ratio of hedge funds is overstated
• The average Sharpe ratio of real estate funds has decreased

Answer: B