Throughout most of my career, the S&P 500 has been an appropriate bogey to assess manager performance. More than that, it's the most widely used benchmark in the capital markets.

But today, it doesn't represent the broad-based, diversified exposure to the U.S. economy that most participants take for granted when investing passively or measuring manager skill.

This WTT, When the Benchmark Becomes a Bet, considers the evidence, implications, and challenges posed by the current composition of the S&P 500.

Read Ted's blog here.