A conglomerate merger is a deal in which a company acquires a target in an unrelated industry, combining businesses with no direct supply-chain or product overlap.
The 10 largest conglomerate mergers in history total over $211 billion in combined deal value, led by Berkshire Hathaway's $37B Precision Castparts acquisition (2015), United Technologies + Rockwell Collins ($30B, 2017), Berkshire's $27B BNSF Railway purchase (2009), Berkshire + Heinz ($23.3B, 2013), and Mars + Wrigley ($23B, 2008). Today's biggest conglomerates by Q1 2026 market cap include Microsoft ($3.10T), Alphabet ($2.03T), Amazon ($1.87T), Saudi Aramco ($1.79T), Meta Platforms ($1.32T), and Berkshire Hathaway ($1.03T).
Below: the full ranked list with deal value, year, and sector for each historic merger, plus a card-grid of the 10 biggest conglomerates today and their operating segments.
We built this interactive table to help you get more information about the biggest conglomerate mergers of all time:
Conglomerate M&A: 10 Largest Historic Mergers + 10 Biggest Conglomerates Today
Sortable by deal value, year, or sector. Filter by category to view either the historic-merger ranking or today's market-cap leaderboard.
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You can also look at this tracker we built which shows the most current valuations of the conglomerates post-merger:
10 Biggest Conglomerates Today by Market Cap
Largest multi-industry conglomerates ranked by Q1 2026 market capitalization, with the operating segments that earned each company a place on the list.
The largest conglomerate mergers in history
- Berkshire Hathaway and Precision Castparts merger for $37B in 2015
- United Technologies and Rockwell Collins for $30B in 2017
- Berkshire Hathaway and Burlington Northern Santa Fe for $27B in 2009
- Berkshire Hathaway and Heinz for $23.3 billion in 2013
- Mars Inc. and Wrigleys for $23B in 2008
- United Technologies and Goodrich Corporation for $18.4B in 2011
- Siemens AB and Varian Medical Systems for $16.4B in 2020
- Berkshire Hathaway for Gen Re for $16.2B in 1998
- Danone and Numico for $13B in 2007
- 3M and Acelity for $6.7B in 2009
Examples of the most successful conglomerate mergers
1. Berkshire Hathaway and Precision Castparts merger for $37B in 2015
In 2015, Berkshire Hathaway acquired Precision Castparts for $37 billion in an industrial conglomerate merger. The deal expanded Berkshire's exposure to the aerospace and energy supply chain (Precision makes complex metal components for engines and turbines) and remains Warren Buffett's largest single acquisition to date, despite a partial writedown during the COVID-era aerospace downturn.
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.Â
2. United Technologies and Rockwell Collins merger for $30B in 2017
In 2017, United Technologies acquired Rockwell Collins for $30 billion in an aerospace conglomerate merger. The deal combined two adjacent-industry aerospace suppliers (UTC's engines and aircraft systems with Rockwell's avionics and cabin interiors) and set up the 2020 separation that created Raytheon Technologies and Carrier Global as separate public companies.
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
In 2009, Berkshire Hathaway acquired Burlington Northern Santa Fe (BNSF) Railway for $27 billion in a transportation conglomerate merger. The deal added a Class I freight railroad with no operating overlap to Berkshire's portfolio and is the textbook example of a pure-play conglomerate acquisition driven by capital allocation rather than synergy.
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
In 2013, Berkshire Hathaway and 3G Capital jointly acquired H.J. Heinz for $23.3 billion in a consumer-goods conglomerate merger. The deal was structured as a public-to-private buyout and led to the 2015 merger with Kraft Foods to form Kraft Heinz, one of the largest packaged-food companies in the world. Berkshire later took a $3B writedown on its Kraft Heinz stake in 2019.
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
In 2008, Mars acquired Wm. Wrigley Jr. Company for $23 billion in a consumer-goods conglomerate merger (with Berkshire Hathaway financing $6.5B of the deal). The combination of Mars (chocolate, pet food) and Wrigley (gum, candy) created the world's largest confectionery company, surpassing Cadbury and Hershey at the time.
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
In 2011, United Technologies acquired Goodrich Corporation for $18.4 billion in an aerospace conglomerate merger. Goodrich's landing gear, wheels, and brakes business was folded into UTC Aerospace Systems and became the foundation of the Collins Aerospace business unit (later spun out as part of the Raytheon Technologies merger).
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
In 2020, Siemens Healthineers (a Siemens subsidiary) acquired Varian Medical Systems for $16.4 billion in a healthcare conglomerate merger. The deal combined Siemens's diagnostic imaging business with Varian's cancer-treatment radiation therapy systems and created the largest pure-play oncology medical-technology company in the world.
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
In 1998, Berkshire Hathaway acquired General Re for $16.2 billion in an insurance conglomerate merger. General Re was one of the largest reinsurers in the world; the deal roughly tripled Berkshire's reinsurance book and gave Buffett control of one of the biggest float-generating businesses in the industry, although early years suffered from underwriting losses that took several years to clean up.
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
In 2007, French food group Danone acquired Dutch nutrition company Royal Numico for $13 billion in a consumer-goods conglomerate merger. The deal added Numico's baby food (Nutricia) and medical nutrition businesses to Danone's dairy and water portfolios, doubling Danone's exposure to the high-margin specialized-nutrition category.
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
In 2019, 3M acquired Acelity (the parent of KCI) for $6.7 billion in a healthcare conglomerate merger. Acelity's negative-pressure wound therapy business was folded into 3M's medical solutions division and expanded 3M's healthcare segment by approximately one-third in revenue terms, although the segment was later partially divested as part of 3M's 2024 healthcare spin-out (Solventum).
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.Â
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.Â
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.
Frequently Asked Questions
What companies are conglomerate mergers?
Conglomerate mergers happen when companies from unrelated industries combine. Examples include Berkshire Hathaway, which owns firms across insurance, energy, and retail, and General Electric, which merged with multiple companies over time across aviation, finance, and healthcare.
What is the largest merger in history?
The largest merger in history was AOL’s $165 billion merger with Time Warner in 2000. It created a media and internet giant but later became one of the most discussed examples of overvaluation during the dot-com era.
What are 5 examples of conglomerates?
Five major conglomerates include Berkshire Hathaway, General Electric, 3M, Siemens, and Tata Group. Each operates across different industries such as manufacturing, technology, and finance.
Which two huge businesses have agreed to merge into one?
In recent years, United Technologies and Raytheon merged to form Raytheon Technologies, creating one of the largest aerospace and defense companies in the world. Deals like this show how large-scale mergers reshape global industries.
What is a conglomerate merger?
A conglomerate merger involves companies from unrelated industries joining forces. The goal is usually to diversify business operations and reduce exposure to risk in a single market.
Why do companies pursue conglomerate mergers?
Companies pursue conglomerate mergers to spread risk, enter new markets, and build broader revenue streams. These deals can also create long-term financial stability through diversification.
Are conglomerate mergers still common today?
They are less common now than in past decades. Many companies focus instead on strategic mergers within their own industries to achieve efficiency and scale.
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