The expected netting benefit of a portfolio is evaluated by its netting factor, representing the ratio of netted exposure to gross exposure. The lower the netting factor, the greater the netting benefit (due to stronger diversification).

For $n$ normally distributed positions with average correlation $\rho$, the netting factor is defined as: $Netting Factor = \sqrt{\frac{1 + (n-1)\rho}{n}}$

Let's calculate the netting factors for each candidate:

• Current Position: $n=9$, $\rho=0.35 \implies \sqrt{\frac{1 + 8 \times 0.35}{9}} = \sqrt{\frac{3.8}{9}} \approx 0.649$
• Combination K: $n=4$, $\rho=0.25 \implies \sqrt{\frac{1 + 3 \times 0.25}{4}} = \sqrt{\frac{1.75}{4}} \approx 0.661$
• Combination Y: $n=7$, $\rho=-0.08 \implies \sqrt{\frac{1 + 6 \times (-0.08)}{7}} = \sqrt{\frac{0.52}{7}} \approx 0.272$
• Combination E: $n=10$, $\rho=-0.11 \implies \sqrt{\frac{1 + 9 \times (-0.11)}{10}} = \sqrt{\frac{0.01}{10}} \approx 0.0316$
• Combination W: $n=5$, $\rho=0.55 \implies \sqrt{\frac{1 + 4 \times 0.55}{5}} = \sqrt{\frac{3.2}{5}} \approx 0.800$

Combination E has the lowest netting factor (0.0316), meaning it provides the highest expected diversification and netting benefit.