Stewart Butterfield and Joel Greenblatt: Two Roads to Business Success

Stewart Butterfield and Joel Greenblatt are two well-known names in the business world, but their careers developed in very different directions. Butterfield became famous for building technology products that changed how people work together, most notably Flickr and Slack. Greenblatt earned his reputation as an investor, author, and teacher, best known for Gotham Capital and for the “magic formula” of value investing. They are not business partners and have no documented personal connection.

Who Is Stewart Butterfield?

Stewart Butterfield was born Daniel Stewart Butterfield on March 21, 1973, in Lund, British Columbia, Canada. His early life was unusual: for the first five years of his life he grew up in a log cabin without running water or electricity, as his family lived on a commune in remote Canada after his father left the United States to avoid being drafted for the Vietnam War. The family moved to Victoria when Butterfield was five. As a child he taught himself to code, and he changed his first name to Stewart when he was twelve.

He studied philosophy at the University of Victoria, earning his bachelor’s degree in 1996, and went on to earn a Master of Philosophy from Clare College, Cambridge, in 1998.

From a Failed Game to Flickr

In the summer of 2002, Butterfield co-founded Ludicorp in Vancouver with Caterina Fake and Jason Classon. The company was building a massively multiplayer online game called Game Neverending. The game never launched, but while building it the team created a photo-sharing tool that turned out to be far more interesting than the game itself. That tool became Flickr. In March 2005, Yahoo acquired Ludicorp, and Butterfield stayed on as general manager of Flickr until he left Yahoo on July 12, 2008.

The Flickr story contains the pattern that defines Butterfield’s career: an ambitious plan fails, a side project built along the way turns out to be the real opportunity, and the founder has the flexibility to follow it.

Tiny Speck, Glitch, and the Birth of Slack

In 2009, Butterfield co-founded a new company, Tiny Speck, whose first project was another online game, Glitch, launched in September 2011. Glitch closed in December 2012 because it could not attract a large enough audience. Once again, the valuable thing was not the game but a tool built to support it: an internal messaging system the team had made to coordinate its own work. In August 2013, Butterfield announced the release of Slack, a team communication tool built by Tiny Speck while working on Glitch.

Slack grew fast. After its public release in February 2014 it was adding users at a weekly rate of 5 to 10 percent, and by December 2015 it had more than 2 million daily active users, of whom 570,000 were paying customers. The company went public in June 2019 with an opening price of $38.50 and a market capitalisation of $21.4 billion. In December 2020, Salesforce confirmed plans to buy Slack Technologies for $27.7 billion. Butterfield announced his departure as chief executive in December 2022 and left Salesforce early in January 2023.

Who Is Joel Greenblatt?

Joel Greenblatt was born on December 13, 1957, in Great Neck, New York. He is a graduate of the Wharton School at the University of Pennsylvania, receiving his bachelor’s degree, summa cum laude, in 1979 and his MBA in 1980. At Wharton he co-wrote a paper with Rich Pzena and Bruce Newberg, “How the small investor can beat the market”, published in The Journal of Portfolio Management. He then spent one year studying law at Stanford Law School before dropping out to pursue a career in finance.

Gotham Capital: A Remarkable First Decade

In 1985, Greenblatt started the hedge fund Gotham Capital with $7 million, most of it provided by the investor Michael Milken. Robert Goldstein joined Gotham Capital in 1989 and later became Greenblatt’s long-term partner in running the firm. Between 1985 and 1994, Gotham achieved an annualised return of 50 percent before the general partner’s incentive fees, or 30 percent net of all fees, an extraordinary record built largely on “special situations” such as spinoffs and other corporate restructurings.

In January 1995, Gotham returned all outside capital, approximately $500 million, and from 1995 to 2009 the fund was closed to outside investors. In 2008, Gotham Asset Management was created as the successor to the investment advisory business of Gotham Capital, and as of March 2026 it managed $32.6 billion.

The Magic Formula and The Little Book That Beats the Market

Greenblatt’s most famous contribution to investing is the “magic formula”, introduced in his book The Little Book That Beats the Market, published in 2005 and updated in 2010. The formula is deliberately simple: buy “cheap and good companies”, meaning companies with a high earnings yield and a high return on invested capital. The two ingredients capture the two things that matter most to a value investor: quality and price. Studies from around the world have found that the formula tends to produce long-term outperformance relative to market averages, but also significantly higher short-term volatility, because it concentrates on 20 to 30 stocks. His first book, You Can Be a Stock Market Genius (1997), focused on special situations such as spinoffs, the area where Gotham made its early returns.

Joel Greenblatt as Teacher and Philanthropist

Greenblatt served as an adjunct professor teaching value investing to MBA students at Columbia University’s Graduate School of Business for more than 20 years, and he co-founded the Value Investors Club, a website where a capped membership of 250 approved investors exchange investment ideas. His philanthropy follows the same practical pattern: in 2002 he donated $2.5 million to P.S. 65Q, a public elementary school in Queens, and in 2006 he co-founded the Success Academy Charter Schools.

Stewart Butterfield and Joel Greenblatt Compared

Comparison	Stewart Butterfield	Joel Greenblatt
Main field	Technology and entrepreneurship	Investing and financial education
Best known for	Flickr and Slack	Gotham Capital and value investing
Born	March 21, 1973, Lund, British Columbia	December 13, 1957, Great Neck, New York
Education	Philosophy, University of Victoria and Cambridge	Wharton School, University of Pennsylvania
Primary focus	Building useful digital products	Evaluating businesses and investment opportunities
Professional approach	Product development and experimentation	Financial analysis and disciplined decision-making
Defining achievement	Slack’s $27.7 billion sale to Salesforce	Gotham’s 50% annualised returns, 1985-1994

This comparison does not suggest that the two men followed the same career path. It highlights how different professional skills can contribute to business success.

How Their Approaches to Business Differ

Creating Products Versus Evaluating Businesses

Butterfield’s work involves identifying communication challenges and developing software that helps people address them. A product such as Slack must offer practical value, remain easy to use, and adapt to the changing needs of organisations. Greenblatt approaches businesses from the other side: rather than building the products himself, he evaluates whether companies have attractive financial characteristics and whether their shares are available at reasonable prices. Both activities require careful analysis, but they answer different questions: “What should we build?” and “Is this business worth owning at this price?”

Experimentation Versus Investment Discipline

Technology development often involves testing ideas, gathering user feedback, and changing direction when evidence suggests a better solution. Butterfield’s career illustrates why flexibility can be valuable: both Flickr and Slack emerged from projects that failed in their original form. Investing requires discipline too, although it applies that discipline differently. Greenblatt’s philosophy emphasises systematic evaluation rather than making decisions because a stock is popular or its price has recently risen.

What Entrepreneurs Can Learn From Stewart Butterfield

Butterfield’s career provides several practical lessons for people who want to build a business or develop a digital product. Start with a real problem: a product has a stronger purpose when it addresses a challenge that people genuinely experience. Pay attention to users, because customer feedback can reveal problems that developers might otherwise overlook. Allow room for experimentation, since an early idea may lead to a different and more valuable opportunity. Focus on usability, so a product helps users complete tasks without creating unnecessary complexity.

What Investors Can Learn From Joel Greenblatt

Greenblatt’s work offers useful principles for people studying investment analysis, and they require careful application: none of them is a guarantee of profit. Understand the underlying business, learning how a company generates revenue and what drives its profitability. Examine financial performance, because revenue growth alone does not establish that a business is profitable or financially strong. Consider valuation: a good company may still be an unattractive investment if its shares cost too much. Use a consistent process, since clear evaluation criteria can reduce decisions driven by excitement or fear.

Can Their Careers Offer Lessons for Business Owners and Investors?

Yes. Butterfield’s experience encourages people to understand customers, develop useful products, and adapt when circumstances change. Greenblatt’s work encourages people to examine financial evidence, evaluate business quality, and consider the price of an opportunity. Neither approach eliminates risk. The value lies in making informed decisions rather than assuming that any particular strategy will always succeed.

Frequently Asked Questions About Stewart Butterfield and Joel Greenblatt

Who are Stewart Butterfield and Joel Greenblatt?

Stewart Butterfield is a technology entrepreneur known for co-founding Flickr and founding Slack. Joel Greenblatt is an investor, author, and educator known for value investing, Gotham Capital, and his “magic formula”.

Are Stewart Butterfield and Joel Greenblatt business partners?

No. They are not known to be business partners. Their professional careers belong to different fields: Butterfield to technology entrepreneurship and Greenblatt to investing and financial education.

What is Stewart Butterfield best known for?

He is best known for co-founding Flickr and for founding Slack, the workplace messaging platform that Salesforce bought for $27.7 billion in 2020.

What is Joel Greenblatt famous for?

He is famous for founding Gotham Capital in 1985, for his “magic formula” of buying cheap, high-quality companies, and for his book The Little Book That Beats the Market.

What is Joel Greenblatt’s magic formula?

It is a simple value-investing method: rank companies by earnings yield and return on capital, then buy the ones that score well on both, meaning companies that are both cheap and good.

Stewart Butterfield and Joel Greenblatt never needed to meet for their careers to belong in the same conversation. One shows what happens when a founder listens to users and follows the evidence, even when it means abandoning the original plan. The other shows what happens when an investor sticks to a simple, evidence-based process for decades.

Related: John Zimmer and Joseph Lau