Family businesses often begin with siblings pooling their talents, ambitions, and energy. Working together offers trust and shared vision—but it can also carry the seeds of rivalry. As businesses grow, brothers sometimes face a critical question: stay together or part ways?

The answer shapes not just their companies but their legacies. Some separations ignite feuds that fracture families and divide communities. Others, however, create space for growth and allow both brothers to thrive.

The story of my grandfather, Patrick McNicholas, and his brother Michael, is a striking example of the latter. Their journey contrasts sharply with more famous brotherly splits such as the Dassler brothers of Adidas and Puma, or the Ambani brothers of India’s Reliance empire.

A Tale of Two Mayo Brothers

Patrick McNicholas was born in 1908 in Bohola, County Mayo, Ireland. He was my grandfather. Like many of his generation, he left home young to seek work abroad, finding labouring jobs on construction sites north of London. In 1945, after World War II, Patrick joined forces with his brother Michael to form PM Brothers, later known as McNicholas Construction.

From humble beginnings—digging deep trenches by hand—the brothers earned a reputation for innovation and reliability. They were among the first to import mechanised trenchers from the U.S., dramatically increasing efficiency. Their work expanded rapidly, laying utilities and cabling across post-war Britain.

By 1957, the brothers decided to separate their interests. Patrick continued with McNicholas Construction, while Michael established McNicholas Cable & Engineering Ltd. Far from a feud, this was a strategic decision: two paths, two visions. Both businesses went on to thrive, each becoming a multimillion-pound enterprise employing thousands of people.

Crucially, there was no bitterness. The McNicholas brothers demonstrated that a split could be handled with respect, leaving space for both sides to succeed and for the family legacy to flourish across generations.

When Splits Turn Sour: The Dassler Brothers

Contrast this with the story of Adolf ("Adi") and Rudolf ("Rudi") Dassler, the German cobblers who founded the Dassler Brothers Shoe Factory in 1924. Their early success was remarkable—most famously when Jesse Owens wore their shoes in the 1936 Berlin Olympics.

But after the Second World War, tensions between the brothers boiled over. In 1948 they parted ways: Adi formed Adidas, while Rudi launched Puma.

The split wasn’t just professional; it was deeply personal. Herzogenaurach, their hometown, became known as the “town of bent necks” because residents would glance down at strangers’ shoes to see whether they were loyal to Adidas or Puma. The feud was so bitter that the brothers never reconciled, even in death.

Both companies went on to become global sportswear giants, but the family relationships were permanently destroyed. The Dasslers illustrate how sibling rivalry can poison legacy, even when the businesses themselves succeed.

High-Stakes Conflict: The Ambani Brothers

Another striking example comes from modern India. When Reliance founder Dhirubhai Ambani died in 2002 without leaving a will, his two sons—Mukesh and Anil—were left to divide one of India’s most powerful conglomerates.

What followed was years of acrimony, played out in courtrooms, boardrooms, and the media. Their mother, Kokilaben Ambani, eventually brokered peace in 2005–06 by dividing the empire: Mukesh took control of Reliance Industries (oil, petrochemicals, refining), while Anil received telecom, power, and entertainment businesses under the Reliance ADA Group.

The outcomes couldn’t have been more different. Mukesh thrived, becoming Asia’s wealthiest man with a fortune exceeding US $100 billion. Anil, meanwhile, saw his businesses collapse under debt and mismanagement; once worth over US $40 billion, he declared bankruptcy in 2020 and today his net worth is a fraction of his brother’s.

The Ambani saga shows the cost of unresolved rivalry: not just reputational damage, but also divergent fortunes that echo long after the split.

Cable laying across a river. Grandfather wearing a fedora hat

Lessons from Brothers Who Split

These three stories—the McNicholas, Dassler, and Ambani brothers—illustrate a spectrum of outcomes when family partners divide:

Strategic Split (McNicholas): A respectful decision to go separate ways, creating space for both businesses to prosper.
Feuding Split (Dassler): A rivalry so toxic it divided a whole town and destroyed family bonds, despite commercial success.
Conflict-Mediated Split (Ambani): A high-stakes feud that needed outside mediation, leading to dramatically unequal outcomes.

What can family businesses learn from this?

Clarity Matters. The absence of clear succession planning, as in Reliance, can unleash chaos. Setting structures early helps avoid destructive disputes.
Respect over Rivalry. The McNicholas brothers demonstrate that differences in vision don’t need to escalate into animosity. Respectful separation can preserve both family ties and business value.
Legacy Is More Than Profit. While Adidas and Puma grew into global brands, the brothers’ feud left a bitter legacy. Contrast that with Patrick and Michael McNicholas, whose enterprises became part of a positive multi-generational story.
The Human Factor. Splits are rarely just about strategy—they are deeply personal. Ego, pride, and family dynamics play as much a role as market opportunities.

Final Reflection

Splitting a business between brothers can either strengthen the legacy or leave lasting scars. The McNicholas brothers’ story proves that it is possible to part ways constructively, ensuring that both family and enterprise flourish.

By contrast, the Dassler and Ambani sagas remind us that when conflict and ego dominate, even the most successful companies can carry the shadow of broken family bonds.

For today’s family businesses, the lesson is clear: disagreements may be inevitable, but how you handle them will define your legacy.

Brothers in Business: When Splitting Strengthens the Legacy