Most indexes, like the S&P 500 and Nasdaq Composite, assign a higher weighting to the largest companies by market cap. For example, Apple has roughly 11 times the market cap of Coca-Cola, so it has a much higher weighting in the S&P 500. But in the Dow, Apple is the 12th highest-weighted company by market cap because the index is price-weighted.

Short-term bearish investors can profit from declines in the Dow Jones with ProShares Short Dow30 ETF (DOG), but it's not ideal for long-term investment.

For Nvidia (NVDA) , this has been the best of years. The company, led by Jensen Huang, makes the graphic processing chips that are the foundation of artificial intelligence, and everyone wants a piece of the company.