This post was originally published on January 13, 2021 and has been updated for relevancy on September 20, 2024.

By virtue of their very nature, large conglomerates have all conducted M&A at some stage in their past.

Conglomerates are traditionally defined as a multi-industry company. However, while past conglomerates moved into new industries with little thought of how their various businesses would fit together, today’s conglomerates are often more focused on product fit and synergy–think Amazon augmenting its delivery business with groceries from Whole Foods. 

But regardless of its strategy, these conglomerates are all formed through acquisitions. As a result, some of the biggest conglomerates in the world are now the companies that come up in everyday conversation: Microsoft, Alphabet, Meta, Walmart, and more. 

Below, we look at the 10 largest mergers and acquisitions ever made by conglomerates.

Examples of the most successful conglomerate mergers

1. Berkshire Hathaway and Precision Castparts merger for $37B in 2015

Inevitably, Warren Buffett’s acquisitions occupy several places on this list and his biggest deal of all came in 2015, with the acquisition of this manufacturer of parts for the aerospace industry.

Interestingly for Buffett, who is famed for his value investing, Precision Castparts was acquired for a multiple in excess of 20 times its earnings, a price that included a 20% premium on the share price. 

2. United Technologies and Rockwell Collins merger for $30B in 2017

When United Technologies acquired Rockwell Collins in 2017, it led to a series of spin-offs, including that of Otis Elevators, a well-known name in consumer tech that left the conglomerate’s portfolio.

Interestingly, the deal is the second aerospace merger in the top three positions, suggesting that it is a focus industry for conglomerates. Despite the deal allowing United Technologies to become a so-called “mega supplier” for Boeing, shareholders were not impressed, with the stock falling to its lowest price in 2 years after the deal was made public.

3. Berkshire Hathaway and Burlington Northern Santa Fe merger for $27B in 2009

When Berkshire Hathaway acquired Burlington Northern Santa Fe, Warren Buffett said:

“Our country’s future prosperity depends on it having an efficient and well-maintained rail system.”

That must have been what he saw in BNSF, the largest acquisition in history for Berkshire Hathaway at that time. The subsequent growth of BNSF’s business, nearly double what it was at that time, appears to have justified the enormous outlay.

4. Berkshire Hathaway and Heinz for $23.3 in 2013

This acquisition is interesting because it paved the way for Heinz to merge with Kraft to create what’s known today as Kraft Heinz, a behemoth in the global food industry. Of the two, Berkshire Hathaway has admitted that Heinz (in which it entered into a partnership with Brazilian private equity firm 3G) was a much better purchase.

The deal also shows the power of conglomerates in several industries: Berkshire Hathaway owns Kraft Heinz and is the largest shareholder in Coca-Cola, among other well-known food brands.

5. Mars Inc. and Wrigleys merger for $23B in 2008

Readers familiar with the mechanics of this deal will recall that it is yet another that Berkshire Hathaway could justifiably claim to have an involvement in.

The conglomerate provided Mars with the financing to acquire Wrigleys in 2008, at a time when most financial institutions were finding liquidity hard to come by. The deal was a match made in heaven, with one of the world’s largest confectioners adding the world’s largest chewing gum brand to its portfolio.

6. United Technologies and Goodrich Corporation merger for $18.4B in 2011

The acquisition of Goodrich Corporation by United Technologies in 2011 allowed UTC to merge its new acquisition with an existing firm in its portfolio, Hamilton Sundstrand, to create a new unit called UTC Aerospace Systems.

At the time of the acquisition, the company’s CEO said the acquisition was “transformational,” which is a bold statement given how often conglomerates tend to make acquisitions. However, the deal may have paved the way for the even bigger acquisition of Rockwell Collins just six years later (see no. 2 on this list).

7. Siemens AB and Varian Medical Systems merger for $16.4B in 2020

Siemens has increasingly invested in medical technology over the past decade through its Siemens Healthineers arm.

The acquisition of Varian in 2020 gives it a leading position (and strong portfolio) in the fight against cancer. Before the acquisition, Varian was considered a world leader in radiotherapy technology and multidisciplinary cancer care. The acquisition valued Varian, a company based in Paolo Alto, at a 24% premium to its listed price.

8. Berkshire Hathaway merger for Gen Re for $16.2B in 1998

Insurance and reinsurance companies have traditionally been targets for Berkshire Hathaway because they provide investors with fast access to liquidity, creating good reinvestment opportunities when they’re available.

The conglomerate already owns several well-known insurance companies like GEICO, creating huge synergies in their portfolio between the companies. However, in a rare error of judgment, the company paid for General RE with its own shares rather than cash. The same stock is now worth close to $100 billion.

9. Danone and Numico merger for $13B in 2007

When Danone bought Numico in 2007, it paid a significant 44% premium over its listed price. The deal marked its first foray into baby foods, an area that it has made several acquisitions in in subsequent years. Numico is the manufacturer of well-known consumer brands in the baby food space such as Milupa and Cow & Gate.

It also provided the firm with a launchpad into higher growth as its existing line of products, which included Evian Spring Water and Activia yogurts, had seen sluggish growth for a few years before the transaction.

10. 3M and Acelity merger for $6.7B in 2009

3M is a company that has never been afraid to move into new spaces. When it stumbled upon the Post-it concept, instead of backing away from the inherent opportunity, it commercialized it into a billion dollar product.

The maker of Post-its is also a maker of wound dressings, so it made sense to acquire Acelity, a maker of wound dressings and other products to stop bleeding, in 2007. The acquisition served to make 3M the world leader of this niche.

10 largest conglomerates by market cap today

In past decades, conglomerates were easier to spot. The holdings of long-ago companies like Textron and Gulf and Western could include mining equipment to batteries to books. However, as scrutiny increased over these conglomerates and investors began to realize that the sum total of their individual acquisitions were often worth more than the conglomerate itself, companies began to become more focused.

Fast-forward to today and you’ll still find a handful of traditional “true conglomerates” (e.g., Berkshire Hathaway), but most companies can now be more accurately classified as “neo-conglomerates”: those which are not shy about expanding into new markets but still try to ensure each part supports the whole. 

This is particularly embodied by tech companies, which have used their considerable market power to acquire a range of different companies that are all, nevertheless, related in some way. For instance, many of Alphabet’s acquisitions have been made in order to buttress its long-standing dominance of its Google search engine.

With all that said, here are the 10 largest conglomerates according to their 2024 market cap:

1. Microsoft – $3.1 trillion

Second only to Apple by market cap, Microsoft has taken a more expansive strategy than its more focused competitor by acquiring well over 200 companies. While all of these could be classified as “tech,” Microsoft has broadened its reach with key entries into industries like video gaming and telecommunications.

2. Alphabet – $2.03 trillion

Like Microsoft, Alphabet has taken a broad strategy toward becoming the giant conglomerate it is today. In some ways, it could be called even more diverse. In addition to the usual list of technology acquisitions, Alphabet has branched off into robotics, automation, and even podcasts.

3. Amazon – $1.87 trillion

With its origins as an online book retailer, Amazon has since earned its moniker as the world’s largest online retailer. But its forays beyond retail are what have made it into a conglomerate. This includes its acquisitions in cloud computing, groceries, and automotives.

4. Saudi Aramco – $1.79 trillion

State-owned Saudi Arabian Oil, more commonly known as Saudi Aramco, has grown into one of the world’s largest conglomerates by maintaining a laser focus on all things energy. Its holdings have grown far beyond simply oil to include natural gas, chemical manufacturing, and much more.

5. Meta – $1.32 trillion

Once just a humble social media company, Meta (Facebook) has followed in Microsoft and Alphabet’s footsteps to become its own vast media empire. Its business now includes advertising, telecommunications, and video games.

6. Berkshire Hathaway – $1.03 trillion

Although it began as a textile manufacturer in the first half of the 19th century, Warren Buffet’s management of the company, beginning in 1965, turned Berkshire Hathaway into one of the world’s largest holding companies. Its assets now include everything from clothing to building products to real estate.

7. Broadcom – $757.9 billion

Broadcom began its history as a semiconductor manufacturer for the broadband industry. But after 40 or so acquisitions, it has become one of the world’s most significant tech conglomerates. Its reach now includes computers, telecommunications, and even AI.

8. JPMorgan Chase – $639.6 billion

JPMorgan Chase achieved its status as the world’s largest privately owned bank mainly through its many acquisitions of smaller banks. Prominent examples include Bear Stearns, Washington Mutual, and First Republic Bank. 

9. Walmart – $621.2 billion

Walmart got to be the largest physical retailer in the world through its aggressive acquisition strategy. All over the world, the company has acquired all manner of shops, from groceries to clothing stores to other general retailers.

10. UnitedHealth Group – $545 billion

UnitedHealth Group has become a giant insurance industry conglomerate by acquiring a variety of different companies, mostly along the healthcare continuum. These include companies in the hospice and palliative care space, as well as those in healthcare technology.