Comment by zmgsabst

Indexes of SP500 without Boeing should outperform ones including Boeing, if you’re predicting that Boeing will underperform in 25 years. You don’t have to short; you can use the knowledge to tune your retirement holdings.

You could even weight the index ratios by how self-cannibalizing you believe each company will be.

Requires a broker that does fractional shares or a lot of money, though.