On any given day, a stock's price reflects the current balance of investors' hopes and fears for the underlying company's future. Over the long term, that stock price will also reflect its actual business results and legitimate prospects, but that long term value rarely matches the stock's current price.

As a result, if there's an upside to market crashes, it's that it often takes a full-on crash to make the shares of strong companies available at legitimate bargain prices. For patient investors with a long term focus, that can make the roughest markets the best times to buy. That makes it important to have a list of companies you'd be willing to buy when prices are low. With that in mind, here are three stocks I already own and that I would be willing to buy more of if the market crashes.

Investor watching the market crash.

Image Source: Getty Images

No. 1: An auto parts giant

Genuine Parts (GPC 1.60%) is perhaps best known for the NAPA Auto Parts chain. Auto parts has a reputation of being a somewhat countercyclical business, performing well when times are tough. This makes a ton of sense. After all, if your choice is to spend a few hundred dollars fixing up your existing older car or spend tens of thousands on a new vehicle, why spend the bigger amount if you're worried about your finances?

That countercyclical nature makes the business of car parts one that should hold up well during rough market and economic times. If its shares get knocked down alongside a generally crashing market even though its business is holding up well, that puts Genuine Parts near the top of my list to buy more of.

No. 2: An everyday essentials food business

J.M. Smucker (SJM 1.19%) makes peanut butter, jelly, coffee, and cat food. When it comes to investments poised to deliver rapid growth, J.M. Smucker doesn't really top anyone's list. When it comes to companies that make products people either can't or won't live without, it certainly looks much more appealing.

The reality is that all people -- and their pets -- have to eat. In a time and place where people are worried about money, homemade peanut butter and jelly sandwiches and home brewed coffee are lower-cost alternatives to restaurants and coffee shops.

As a result, there's a really good chance that J.M. Smucker's business will hold up well in tough times, even if a market crash knocks its shares down. Given that it currently trade at around 16 times its expected forward earnings, it wouldn't take much of a market crash to make it a clear bargain worth it for me to consider scooping up additional shares.

No. 3: America's largest independent railroad 

Union Pacific (UNP 1.22%) is America's largest railroad that trades as an independent stock. When it comes to moving a lot of freight around, it's hard to beat the price tag that railroads offer. 

Railroads do depend on a reasonably strong economy to maximize the amount of freight they move around. Still, the fact that they can move that stuff around at a relatively low cost makes it likely shippers will stick with them even as they are cutting back other transportation methods. That makes their revenue a bit more resilient than other, even more economically sensitive ways of moving stuff around.

Still, in a market crash, particularly one associated with an economic slowdown, it's quite possible that Union Pacific's shares could get knocked down along with other freight movers. If that crash is deep enough to make Union Pacific a clear value, it's another stock I currently own where I'm willing to invest more money.

Solid companies at decent values can make great long-term investments

If there's one thing that Union Pacific, J.M. Smucker, and Genuine Parts have in common, it's that they all operate in core business lines that are central to many people's lives. They may not be the most exciting and fastest growing stocks around, but when the market is crashing, they're exactly the sort of more defensive businesses that have a shot of sticking around.

It's hard to predict when the next stock market crash will happen. Yet if you're prepared with a list of what you're willing to buy when the market offers up bargains as part of that crash, you'll be more likely able to take advantage of it when (not if) it does take place. So make today the day you build out your list of what you'll be willing to buy. Like my list, yours may very well include stocks you already own. Whether or not it does, having that list will put you much more in the driver's seat in that next crash.