Which of the following is NOT a version of a commodity index?

A capital return index is not typically recognized as a version of a commodity index. Commodity indices are designed to track the performance of commodity markets, and they generally focus on reflecting the price movements and returns of various commodities.

The total return version of a commodity index reflects both price movements of the underlying commodities and any income generated from holding those commodities, such as roll yield from futures contracts. This approach provides a comprehensive view of the returns an investor could expect beyond just price changes.

The excess return index, on the other hand, measures the returns of a commodity index relative to a risk-free rate, often providing insights into the performance of commodities when compared against a benchmark.

A spot index would typically focus on the immediate prices of commodities sold for settlement, capturing the market value at a particular moment in time without factoring in future contracts or interest from roll yield.

In contrast, the capital return index does not align with the concept of commodity indices as it generally pertains to equity markets, focusing solely on price appreciation without accounting for any income generated from those investments. Thus, it is appropriate to identify capital return as the option that does not represent a version of a commodity index.