Short answer: S&P 500 Index ETF returns will not be affected in the long run.

Here are the reasons:

• S&P 500 index is balanced and spread across different industries, thus it is impossible for all the industries to perform badly the same time.
• There are 500 companies inside the index, that means individual company stock only weight 1/500 or 0.2% of the whole index.
• If all the S&P 500 index stocks perform badly, that will mean all the industries is perform badly, so it will not affect the index position.
• Those inside S&P 500 are selected according to capital and various factor. And a company with huge capital usually will not be wiped out overnight. Even during a panic sells, there are value buyer able to salvage the remaining asset value to support it.
• Due to the above reason, S&P 500 index ETF can always take time to track and balance the stock, i.e. sell-off those stock drop out of S&P 500 index, buy the newcomer.
• the S&P 500 index ETF tracking practice will cause matthew effect to involved stock(the loser stock will fall further, the newly entry stock will go higher). Since each company only weight 0.2%, it hardly dents the ETF coffer.

Short answer: S&P 500 Index ETF returns will not be affected in the long run.

Here are the reasons:

1. S&P 500 index is balanced and spread across different industries, thus it is impossible for all the industries to perform badly the same time.
2. There are 500 companies inside the index, that means individual company stock only weight 1/500 or 0.2% of the whole index.
3. If all the S&P 500 index stocks perform badly, that will mean all the industries is perform badly, so it will not affect the index position.
4. Those inside S&P 500 are selected according to capital and various factor. And a company with huge capital usually will not be wiped out overnight. Even during a panic sells, there are value buyer able to salvage the remaining asset value to support it.
5. Due to the above reason, S&P 500 index ETF can always take time to track and balance the stock, i.e. sell-off those stock drop out of S&P 500 index, buy the newcomer.
6. the S&P 500 index ETF tracking practice will cause matthew effect to involved stock(the loser stock will fall further, the newly entry stock will go higher). Since each company only weight 0.2%, it hardly dents the ETF coffer.

Short answer: S&P 500 Index ETF returns will not be affected in the long run.

Here are the reasons:

• S&P 500 index is balanced and spread across different industries, thus it is impossible for all the industries to perform badly the same time.
• There are 500 companies inside the index, that means individual company stock only weight 1/500 or 0.2% of the whole index.
• If all the S&P 500 index stocks perform badly, that will mean all the industries is perform badly, so it will not affect the index position.
• Those inside S&P 500 are selected according to capital and various factor. And a company with huge capital usually will not be wiped out overnight. Even during a panic sells, there are value buyer able to salvage the remaining asset value to support it.
• Due to the above reason, S&P 500 index ETF can always take time to rebalance the ETF, i.e. sell-off those stock drop out of S&P 500 index, buy the newcomer.
• the S&P 500 index ETF rebalances will cause matthew effect to involved stock(the loser stock will fall further, the newly entry stock will go higher). Since each company only weight 0.2%, it hardly dents the ETF coffer.

Short answer: S&P 500 Index ETF returns will not be affected in the long run.

Here are the reasons:

• S&P 500 index is balanced and spread across different industries, thus it is impossible for all the industries to perform badly the same time.
• There are 500 companies inside the index, that means individual company stock only weight 1/500 or 0.2% of the whole index.
• If all the S&P 500 index stocks perform badly, that will mean all the industries is perform badly, so it will not affect the index position.
• Those inside S&P 500 are selected according to capital and various factor. And a company with huge capital usually will not be wiped out overnight. Even during a panic sells, there are value buyer able to salvage the remaining asset value to support it.
• Due to the above reason, S&P 500 index ETF can always take time to track and balance the stock, i.e. sell-off those stock drop out of S&P 500 index, buy the newcomer.
• the S&P 500 index ETF tracking practice will cause matthew effect to involved stock(the loser stock will fall further, the newly entry stock will go higher). Since each company only weight 0.2%, it hardly dents the ETF coffer.