An ultra-low expense ratio is not the end of the story when it comes to selecting an index fund manager.

At low fee levels, performance differences between funds depend more on the less visible and complex elements of index fund management.

Investors should consider a broader set of complex factors, such as organisational incentives, portfolio management capabilities, securities lending practices, pricing policies and scale.

We present a decision-making framework for the most popular, broad-based equity and fixed income index funds.