Michael Rubens Bloomberg

Salomon Brothers fired Bloomberg in 1981, at 39, and paid out his partnership stake at about $10 million.¹ By his own account he started the next company the following morning. That company is Bloomberg LP, a private financial data, software, and media firm whose core product, the Bloomberg Terminal, is the dominant real-time financial information and trading-analytics platform used by traders, analysts, and institutions across Wall Street and global finance; Bloomberg is its founder and majority owner. He later served three terms as mayor of New York City. The company has never gone public; Bloomberg holds a stake of roughly 88 percent.

Background

Bloomberg was born on February 14, 1942, in Medford, Massachusetts, to a lower-middle-class Jewish family. His father, William Henry Bloomberg, was a bookkeeper for a dairy who never earned more than about $6,000 a year; the family reportedly used an Irish attorney as a proxy buyer to purchase their home because of anti-Semitic housing restrictions. Bloomberg became an Eagle Scout, one of the youngest at the time.

He studied electrical engineering at Johns Hopkins University, working as a parking-lot attendant to help pay tuition. During his junior year, in 1963, his father died of heart failure, an event Bloomberg has cited as instilling a new intensity and drive.¹ He earned an MBA from Harvard Business School in 1966. Scouting, engineering training, and his father's death are the most commonly cited formative threads in his biography.

Getting started

Bloomberg joined Salomon Brothers in 1966, reportedly starting by counting stock certificates in the firm's vault. He rose to head of equity trading and sales and was said to be the youngest partner in the firm's history. In 1979 he was moved into computer and systems operations, a shift widely described, including in his own account, as effectively a demotion.¹

That systems role became his technical education. He spent roughly two years learning how financial data moved through Wall Street and where the informational gaps lay between the sell side and the buy side, the most repeated causal detail in his biography, consistently cited as the training that made his founding insight possible.

In 1981, at age 39, Bloomberg was fired when Salomon Brothers merged with the commodities trading firm Phibro, receiving a partnership payout of about $10 million.¹ He has described his founding insight in his own words: "The stock market was strictly a one-way street, sellers having all the power because they had all the knowledge... We went out and we built a product for the buy side... and we leveled the playing field."² He has also said that had Goldman Sachs offered him a job he would have taken it: "Thank God for that." By his account he started the company essentially the next morning.

What he built

Bloomberg founded Innovative Market Systems, which built a computer terminal, originally called Market Master, to deliver real-time bond pricing, analytics, and later equities and market data to buy-side clients who lacked the sell side's information advantage. His commonly cited early partners are Thomas Secunda, Duncan MacMillan, and Charles Zegar.³

The first customer was Merrill Lynch, which in December 1982 bought 20 terminals and made an equity investment reported as roughly $30 million for a 30 percent stake; figures vary by source, but Merrill's role as first customer and investor is well corroborated.³ The product was later renamed the Bloomberg Terminal, and the company became Bloomberg LP.

The terminal business grew into the dominant financial-data platform and expanded into news with Bloomberg News, founded in 1990, plus television, radio, the Businessweek acquisition, and Bloomberg Law. Mid-2020s estimates vary widely, with annual revenue placed at roughly $5 billion to $15 billion and employee counts around 20,000 to 26,000 or more. The company has never held an initial public offering.

How he operates

Bloomberg is known for a distinctive workplace philosophy of no private offices, running an open-plan bullpen culture at Bloomberg LP and later carrying the same layout into New York City Hall as mayor, sitting at an open desk pod alongside staff.² He treats information asymmetry as an engineering problem to be solved rather than a trading edge to exploit personally; the company sold information access by subscription rather than trading against its customers, a data-and-systems-first approach to a business every competitor of the era ran on relationships. He has repeatedly framed the business as a fairness and access mission: "We leveled the playing field." Through Bloomberg Philanthropies he has given away tens of billions of dollars toward public health, gun control, climate, the arts, and government innovation, and has signed the Giving Pledge.

Where things stand

Bloomberg LP remains fully private, with Bloomberg holding a controlling stake of roughly 88 percent and remaining founder and chairman even after ceding the CEO title in 2023 to longtime product chief Vlad Kliatchko. Former Bank of England governor Mark Carney has been reported to chair a newly formed board. Bloomberg served three terms as mayor of New York City from 2002 to 2013, winning first as a Republican, then as an independent, then a Democrat, reportedly spending about $650 million of his own money across those campaigns. He ran unsuccessfully for the 2020 Democratic presidential nomination, spending over $500 million before withdrawing, and continues to run Bloomberg Philanthropies. His personal net worth was estimated at around $105 billion to $110 billion in early to mid 2026.

Key facts

• Fired from Salomon Brothers at 39 with a payout of about $10 million, Bloomberg started what became Bloomberg LP essentially the next morning.
• First customer Merrill Lynch bought 20 terminals in December 1982 and took a reported 30 percent equity stake for about $30 million, a customer that was also a strategic investor.
• His personal fortune was estimated at roughly $105 billion to $110 billion in 2026, built through a company kept fully private with no IPO in more than 40 years.
• He spent an estimated $650 million of his own money across three campaigns to become mayor of New York City, then over $500 million self-funding a losing 2020 presidential run.
• Bloomberg maintains a zero private offices policy, carrying the open bullpen desk layout from company headquarters into City Hall during his mayoralty.