Thomas Gallagher and the six percent that needed a room

Thomas Gallagher helped build a company devoted to electronic trading, then gave it a room where people could shout. In September 2025, MIAX Sapphire opened its options trading floor in Miami. The business had spent years making transactions happen inside computers. Now it had to think about sight lines, acoustics and where everybody would stand. Even a market measured in fractions of a second occasionally needs a good floor plan.

The apparent detour makes sense when you follow Gallagher’s career. Before he became an exchange executive, he was a securities lawyer helping businesses raise money. He knew that a transaction required willing participants, workable terms and permission to proceed. At MIAX, those concerns grew into the architecture of an entire business. Software would carry the orders. Relationships would help bring them in.

A lawyer changes sides of the desk

Gallagher was a founding partner of Gallagher, Briody & Butler in Princeton, New Jersey. His work covered corporate and securities law, including financing for public and private companies. He earned his law degree at Capital University Law School; Rutgers University also appears in his education. The professional groundwork was close to the mechanics of enterprise: how money arrives, what investors receive and how an ambitious proposition becomes a binding agreement.

That background gave him a practical part to play in starting MIAX. He helped assemble the capital and recruit experienced industry people. The founder’s task included persuading others that another venue for trading deserved their attention. An exchange has a peculiar opening problem: it needs customers whose presence makes it more useful to other customers. A beautifully engineered empty market is still empty.

He became chairman in 2008 and chief executive in 2012. That December, he left his law firm association and joined the company full time. MIAX Options began trading on December 7, 2012. The move put him on the operating side of a business whose requirements went well beyond getting a financing transaction over the line. It needed to open, function and persuade participants to return.

The customers have a place in the machinery

At a SALT panel in 2021, Gallagher described the founding thesis in unusually manageable language: “invest in technology, invest in people and keep them together.” Keeping them together is the part that turns a recruitment exercise into a management career. The technology was built in-house. The people using it were central to how the business developed.

He also explained that member firms were shareholders. Their relationship to MIAX extended beyond sending orders to a screen. The arrangement gave participants an ownership interest in the venue they helped populate. His account of creating liquidity combined technology and those partnerships. For a founder with a financing background, bringing capital providers and customers into the same conversation was familiar territory.

The discussion moved through digital assets, regulation and the usefulness of having different exchange permissions. Gallagher’s contribution was grounded in what the company could legally operate. Owning securities and futures exchanges offered room to develop products across regulatory frameworks. The lawyer was still present in the executive: before building the next thing, understand the permissions underneath it.

“invest in technology, invest in people and keep them together.”

Thomas Gallagher · SALT, 2021

Four doors into the options market

The options business developed through a succession of launches. MIAX Pearl followed in February 2017, Emerald in March 2019 and Sapphire’s electronic exchange in August 2024. These venues offered different combinations of pricing and order allocation. For participants, the differences affected the economics and mechanics of trading. For Gallagher, expansion meant offering more ways to do business with the group.

The names sound rather like a jeweller’s window. Underneath them sit decisions about who receives an execution and who pays or receives a fee. Those choices are central to competition between exchanges. Another trading venue becomes useful when its rules, costs and available counterparties fit the business a participant wants to conduct. The technology supports that proposition; it does not relieve the operator of having to make it attractive.

The trading floor completed another part of this plan. Before it opened, MIAX described its electronic options offering as reaching approximately 94% of multi-listed volume. Floor trading represented the remaining approximately 6%. Providing access to that segment required a physical place. The percentages explain why a company with electronic trading at its core acquired an interest in the comparatively ordinary business of construction.

A market with windows

Sapphire’s physical floor began operating on September 12, 2025. The 38,400-square-foot facility occupies the ninth floor of 545 Wyn in Miami’s Wynwood district. It includes offices, conference facilities and a Bloomberg television studio. The panoramic views may be pleasant, but the more consequential design details concern sound, lighting and whether market participants can see one another properly.

Chief information officer Douglas Schafer described work with member firms to accommodate the options industry’s needs while automating manual processes. That is a revealing combination. MIAX was building a place for human interaction while putting its own technology beneath the activity. The floor gave Gallagher’s company a conspicuous presence in its namesake city and another way for customers to execute transactions.

A project like this also has a calendar that cannot be accelerated by faster trading software. Construction delays affected inspections and permitting, and the launch date moved to September. The operational notice dealt with equipment deliveries, connectivity, desktop installations and testing. An exchange opening can involve rather more cable management than the photographs suggest.

The exchange operator becomes a listed company

One month earlier, MIAX had taken its own place in the public market. Its shares began trading on the New York Stock Exchange in August 2025 under the symbol MIAX. The IPO closed on August 15 with 17.25 million shares sold at $23 apiece, including the underwriters’ additional shares. Gross proceeds were approximately $396.8 million, before commissions, discounts and offering expenses.

For someone whose earlier work involved helping companies finance themselves, it was a recognisable transaction on a different scale of personal responsibility. He now led the issuer. The capital raised belonged to a business operating markets for other people, and those new shareholders would have their own expectations about how it performed.

His conversation on the first trading day suggested a measured appetite for the next purchase. After several acquisitions, he wanted to develop products on the platforms already acquired. He discussed protecting exchange licenses, preparing governance for public ownership and investing selectively. The characteristic detail was his attention to trading-system performance even on a day when the company’s own share price supplied an easier talking point.

A wider map, then more to do with it

Gallagher’s chairmanships trace the group’s widening geography. He joined the Bermuda Stock Exchange Council in 2019 and became chairman in February 2020. He joined the board of the former Minneapolis Grain Exchange in 2019, becoming chairman in June 2021. In June 2025, he became chairman of The International Stock Exchange Group, adding another international responsibility.

There is a common operating thread across these different markets. MIAX introduced a new trading and settlement platform for Bermuda in March 2025 and launched its Futures Onyx platform that June. The acquired businesses supplied established markets and permissions; the group’s technology provided a way to develop them. Gallagher’s ambition increasingly concerned what those platforms could carry next.

By October 2026, the next products were tangible. Bloomberg equity index futures had launched earlier in the year. On October 15, MIAX announced that its Tini Bloomberg 500 and Tini Bloomberg 100 futures were available to eligible NinjaTrader customers. The smaller contracts addressed retail traders, extending the business through a platform those customers already used.

Six days later came four physically settled fertilizer futures, trading on Onyx and clearing through MIAX Futures Clearing. Gallagher framed them around price discovery and managing uncertainty in fertilizer supply. The range is striking: a career that began with corporate financing now included markets tied to agricultural inputs as well as equity exposure. Each product still required the old ingredients of participants, rules and a working venue.

The credit goes round the room

In February 2026, FOW named Gallagher Chief Executive of the Year. He used his acceptance remarks to credit the team: “success is never a solo effort.” The dedication fits the public account of his work. Capital raising, recruitment, member relationships and technology all recur. His career has depended on putting the right people into arrangements that give them a reason to stay.

The September 2026 trading figures give that work a scale: 11 million options contracts a day on average for the year to date, and 17.1% of the multi-listed options market. The numbers belong to the group and its participants. Gallagher’s particular contribution has been to help assemble the organisation around them. In Miami, some of those participants can now look across a room at one another. After years spent building electronic markets, he has given part of the business a very human working distance.