Even in 2015, just about every newscast, online story, or random mutterings (my favorite kind of mutterings) about the general stock market always starts off with the Dow Jones Industrial Average, usually followed up by the S&P 500, and then the Nasdaq Composite. Although the S&P 500 index fund (NYSE:SPY) dwarfs the size of the equivalent Dow Jones product (NYSE:DIA) to the tune of a $194 billion market cap to $12 billion, the Dow is still the goto index.

People still talk about the Dogs of the Dow as a thing, and I wrote about it back in 2010(!) when this blog was the internet version of a toddler. Sticking around for 5 years makes me the internet version of a dirty old man, which is actually pretty close to the truth. So I’ve got that going for me.

Back to the Dow Jones Industrial Average. Unlike the S&P 500, which is a market cap weighted index, the Dow just adds up the value of each stock and divides it by 30. It’s a little more complex than that, but not much. It arbitrarily picks stocks to have in the index as well, which leads to a pretty interesting mishmash of an index.

Quiz time! Guess what is the stock with the highest weighting in the Dow Jones Industrial Average. Is it:

a) Exxon Mobil
b) Apple
c) Visa
d) General Electric

The answer is Visa, because of course it is. Visa has a market cap of $167 billion, which makes it the smallest company out of those four by about $100 billion. The second largest company in the Dow is Goldman Sachs, and the third biggest is 3M. Here’s a fun list of the whole top 10:

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Visa is a nearly 10% weight in the index, followed by Goldman Sachs at 6.74%. Between those two companies control nearly 20% of the moves of the Dow Jones. While both of those companies are fine, they’re hardly representative of the overall U.S. market.

For comparison’s sake, let’s look at the S&P 500.

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You’ll notice there’s exactly zero overlap, even though those are the 10 biggest companies in the U.S. There’s plenty of overlap in the Dow 30 and those stocks, but none in the top 10. Johnson and Johnson is the first one to show up, and it’s only the 12th biggest name in the index. Hilariously, Apple, Berkshire, Wells Fargo, and Pfizer don’t even make it onto the Dow, even though they’re all in the top 10 largest companies in America.

The composition of the Dow is changing though, since Visa announced it was splitting its stock 4-for-1, bringing the price down from $272 to the $70 range. This will reduce Visa’s weighting in the Dow from nearly 10% to just under 3%, paving the way for Goldman Sachs to become the largest Dow component. General Electric will continue to bring up the rear, even though it’s the 7th most valuable company in America (and interestingly, the only original member of the Dow Jones Industrial Average to stay in the index for the whole life of it, dating back to the 1800s).

Remember when Apple split its stock last summer? Speculation at the time wondered if the company did it to get into the Dow. Remember, at $700 per share, Apple would have dominated the index more than your overbearing wife before you say the safe word, so there was no way it could be added. But as a $100 per share company, it would be in the middle of the pack.

It’s almost a year later, and we’re still waiting for Apple to finally make it into the Dow. Maybe the guys in charge are BlackBerry fans.

Most people just assume the Dow Jones Industrial Average is a smaller version of the S&P 500. As you can see, that’s not even remotely true. So remember, the next time you look at it, you’re really just checking out the performance of Visa, Goldman Sachs, and other large companies that happen to have high prices. What a joke of an index.

Tell everyone, yo!