Last month, the iconic Dow Jones Industrial Average (^DJI -0.98%) celebrated its 125th anniversary. Originally made up of a dozen components, the Dow Jones was expanded to 30 companies in 1928, which is the figure it's remained at for nearly 93 years.

Since its debut in May 1896, we've witnessed 57 changes to the index. Some have been minor, such as company name changes or spinoffs, while others have involved dropping brand-name companies from the index. Just last year, ExxonMobil, Pfizer, and Raytheon were given their walking papers, with Amgen, salesforce.com, and Honeywell International replacing them. 

The truth of the matter is, these brand-name businesses won't be the last to be given the boot from the Dow. I'd consider the following three Dow components in realistic danger of being given the heave-ho at some point in the not-so-distant future.

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Walgreens Boots Alliance

One of the weird quirks about the Dow Jones Industrial Average is that it's a price-weighted, not market cap-weighted, index. This means the higher a company's share price, the more influence it has over the index. Prior to Apple's stock split, it had more influence than any of the other components. Following its stock split, it's now 21st in overall influence. Pharmacy chain Walgreens Boots Alliance (WBA -1.18%) is dead last, with the lowest share price of the 30 components ($50.84).

Aside from having the least amount of influence within the Dow, there are also four other healthcare companies in the index. One of these is UnitedHealth Group, which has two core businesses. One of these segments is Optum, which encompasses a broad array of healthcare services, including pharmacy-benefit management services. It's not a mirror image of the services Walgreens provides, but Optum would provide a fairly clear picture of what's going on in the pharmacy space.

While I personally like Walgreens Boots Alliance as an investment (and own it in my portfolio), the company is in the midst of executing a multistep turnaround plan that'll take some time to truly pay dividends. S&P Dow Jones Indeces, the entity that decides which companies move in and out of the Dow Jones Industrial Average, may simply lose patience with Walgreens while highly innovative companies see their valuations soar.

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Cisco Systems

Networking infrastructure giant Cisco Systems (CSCO -0.52%) was added to the Dow in June 2009, shortly after the end of the Great Recession. Since its addition, Cisco has gained 162%, which has lagged the Dow by 117 percentage points. To boot, Cisco Systems has the second-lowest share price, behind only Walgreens.

The big knock against Cisco is that it's sort of become a dinosaur among tech stocks. Despite shifting its focus to the cloud and software solutions, the company's sales growth has only been inching higher. Cisco's physical networking products are profitable and generating healthy cash flow, but they also hold back the company's growth rate. 

The one thing Cisco does have going for it is its size. There isn't a networking equipment company even close to Cisco in terms of market cap. The question S&P Dow Jones Indeces will need to ask is whether networking equipment is truly necessary as a Dow component when the world is becoming more digitized by the day. My expectation is they'll eventually show Cisco the door. And if Shopify ever conducts a forward stock split, it'll be Cisco's cue to pack its bags.

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Travelers Cos.

Insurance may be a boring industry, but it does help tell the story of how well or poorly the U.S. economy is faring. The issue for property and casualty insurer Travelers (TRV 0.26%) is that it's been substantially outperformed by its peers since entering the index, and at $36 billion is the smallest company by market cap in the Dow Jones.

One of the more logical reasons to replace Travelers would be the increased visibility, and size, of its peers. After gaining 504% and 389%, respectively, since June 8, 2009 (the date Travelers was added to the Dow), Progressive and Allstate have leapfrogged Travelers to market caps of $54 billion and $37 billion, respectively. Berkshire Hathaway would be the no-brainer addition in the insurance category, if not for its Class A share price of nearly $413,000. The Dow's price-weighted index would go haywire due to Berkshire's astronomical share price.

As for Travelers insurance operations, business is good. Higher net written premiums and a boost in net investment income is helping to offset a big uptick in catastrophe losses in the first quarter. That's the great thing about the insurance industry: premium pricing power always keeps insurers one step ahead of the next catastrophe. Travelers will likely remain a conservative long-term investment, but it may not fit the fold as a Dow component if it keeps underperforming its peers and the index.