It can be tough to choose the right investments for your work-related retirement account. Most have few choices, and fewer allow you to invest in individual stocks. That said, for those who have individual options, we think you should consider buying your company's stock or Cerner Corp (NASDAQ:CERN). Meanwhile, those who don't should consider buying the entire stock market via the Vanguard Total Stock Market ETF (NYSEMKT:VTI) or a similar fund. 

Go with what you know best

Matt DiLallo (Your company's stock): I have only worked for one company that has even offered a 401(k), and the only stock I could buy at the time was that of my employer. However, that's actually not a bad option because it allows you to participate in the value you are creating for the company's investors. As that value increases, it serves as an incentive to continue working hard.

A statement showing 401K plan financials.

Image source: Getty Images.

That said, not everyone would agree with this advice, and for a good reason. Investing in your company's stock concentrates your financial risk. For example, if tough times hit the company, it could be a double-whammy with the potential for you to lose both your job and investment in the company's stock. Just ask former employees of Enron, many of whom lost everything when it went belly up because they loaded up on the stock.

However, there are ways to limit this risk. The most important is to know your company and its industry well enough to determine if it's built to last. Consider whether it operates in a cyclical industry and if there has been a history of layoffs. That would be an ominous sign. On the other hand, if it has consistently grown earnings and cash flow, and has a bright future, then there's no reason you wouldn't want to be an investor, too. That said, in either case, you should keep your allocation to a comfortable level. A good rule of thumb for any investment is to keep it to less than 10% of the whole. That's meaningful enough to make a difference if things go well, but not so much as to cause permanent damage if they do not. 

A top-tier information technology play

Daniel Miller (Cerner Corp): While most of us are stuck with fairly strict parameters on what we can buy in our 401(k) plans, if you're one of the lucky investors with the ability to select individual stocks, Cerner Corp should be on your list of candidates.

Cerner is a leading healthcare information technology supplier that provides a range of software, hardware, and services to thousands of hospitals and facilities around the world. The interesting thing about Cerner is that it develops and creates its own software and services internally, which provides a high-quality and more seamless product than its competitors. Historically, that's led to Cerner creating long-term relationships with its clients, which fuels top- and bottom-line growth.

Another positive factor for investors is that Cerner's clients face high switching costs. Implementation of Cerner's IT products and services can take longer than a year in some cases, and with a service contract lasting even longer, it gives incentive for consumers to keep the same system and products -- especially considering that healthcare information technology is responsible for human lives.

CERN Chart
CERN data by YCharts.

As you can see in the graphic above, Cerner has been able to translate its in-house developed products into a strong brand and consistently growing top and bottom lines. That's not likely to change in the near term, and that's why Cerner should be a top candidate for your 401(k) or owned in the funds you choose.

Stick with the super-simple, super-boring investments

Brian Stoffel (Vanguard Total Stock Market ETF): As Daniel already mentioned, buying shares of anything for your 401(k) can be extremely difficult. Usually, the options are limited to whatever the company that's executing your plan makes available. That's why my suggestion is to go with whatever the broadest, lowest-fee index option is.

For the past decade, the popularity of Vanguard's ETFs have boomed. Instead of turning over large sums of money every year to "professionals" who could beat the market, investors are getting wise and realizing that such "potential" usually goes unfulfilled. In return, they are willing to get market-matching returns and pay very low fees.

I think an investor's best bet is to go with the Vanguard Total Stock Market ETF. The fund has exposure to over 3,500 different stocks -- so there's plenty of diversification. Additionally, its expense ratio is just 0.05% -- extremely low. If your plan doesn't offer this specific ETF, I'd suggest aiming for a fund with similar diversification and low costs.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.