GLG
GLG — formally Gerson Lehrman Group — is the world's largest expert network: a New York City-headquartered research firm that connects decision-makers at investment firms, consultancies, corporations and nonprofits with independent experts who can explain an industry, market or technology from firsthand experience. Founded in 1998 by Yale Law School graduates Mark Gerson and Thomas Lehrman, GLG pioneered the expert-network model, abandoning an original publishing plan in 1999 after discovering that clients would rather talk directly to experts than read formal reports. Its network has been described at more than one million experts in recent company descriptions, its clients include strategy consulting firms, hedge funds, private equity firms and professional services firms, and it operates offices in 22 cities in 12 countries. The firm has been backed by private equity investors Silver Lake Partners, Bessemer Venture Partners and SFW Capital Partners, and since July 2023 it has been led by chief executive Gemma Postlethwaite.
Founding as a publishing house, then the pivot
Gerson and Lehrman founded the firm in 1998 with funding from friends and family, intending to produce industry guidebooks for institutional investors — a publishing house model in which experts' knowledge would be packaged into written products. Alexander Saint-Amand, a former Bloomberg reporter, joined shortly after the founding and went on to serve as president and chief executive until 2018. The publishing plan lasted about a year. In working with their first clients, the founders found that investors did not primarily want written reports; they wanted conversations — the chance to question a practitioner directly and test an investment thesis against lived experience. In 1999 GLG abandoned publishing and began offering subscriptions to its network of experts, creating the template that the entire expert-network industry would follow.
Growth from investors to every industry
GLG's first customers were investors, and most of its growth between 1999 and 2005 came within the investment community — hedge funds and other asset managers paying for calls with physicians, engineers, executives and specialists who understood the companies and products in their portfolios. Around 2000 the firm was holding breakfast sessions at the Yale Club in New York with doctors, researchers and biotechnology investors, and healthcare and technology were its early strongholds. Expansion beyond them followed: into energy and industrials by about 2002, a London office and legal, economic and regulatory practice areas in 2003, and Asian offices in Hong Kong and Shanghai by 2005 as client demand globalised.
In 2006 GLG broadened decisively beyond investors, beginning work with large strategy consultancies and with companies in life sciences, chemicals and industrials, and technology. By 2010 The Wall Street Journal was describing GLG as dominating the United States expert-network industry, and one contemporary industry report credited it with roughly two-thirds of the market. Its expert population grew from the hundreds of thousands cited through the 2010s — 700,000 in company descriptions around the start of the 2020s — to the more-than-one-million figure in current descriptions, recruited across every sector the firm's clients study.
How the service works
GLG's core product is the one-to-one consultation: a client poses a research question, GLG's teams recruit and vet experts fitted to it, and the client speaks with them by phone or video, sometimes moderated or translated. Around that core sit a family of formats. GLG Events bring leading voices together in person, by live video or on demand to discuss trends as they happen, with custom events built around a client's own research objectives. GLG Placements put C-suite-level experts inside a client's team, and GLG Projects engage experts for longer, deeper work such as market assessments, competitive landscape analysis, brand analysis and voice-of-customer studies. GLG Surveys gather quantitative views across populations of experts. A content library adds a recorded layer: transcripts of expert interviews and events — nearly 20,000 transcripts by the time of its July 2023 distribution agreement with Bloomberg, which made GLG interview transcripts searchable on the Bloomberg Terminal, and integrations with platforms such as Sentieo have carried the library further into investors' workflows. Most recently the firm has rebuilt its client platform as myGLG, adding AI-assisted search and synthesis across calls and content on top of its compliance framework.
Who the experts and clients are
The network's breadth is its selling point. GLG's experts include asset managers, investors and consultants; physicians and scientists; engineers; lawyers; current and former senior C-level executives; and former government officials. Its clients span strategy consulting corporations, hedge funds, private equity firms, professional service firms and nonprofit organisations, with the firm describing its recruiters as adding hundreds of new experts every day in earlier company profiles and thousands every week in more recent ones. The model treats expertise as a marketplace: experts are freelancers compensated for their time, and GLG's specialised teams — organised by industry and client type — are charged with matching a question to precisely the right career history, not merely a relevant job title.
Compliance and the insider-trading scrutiny
The expert-network model carries an obvious risk: a consultant who shares material nonpublic information about an employer could feed insider trading. The industry faced intense scrutiny around 2010-2011, when a United States insider-trading investigation ensnared consultants connected to a rival firm, Primary Global Research; GLG itself was not accused of wrongdoing in that probe, but as the industry's largest firm it stood most exposed to any loss of client confidence. GLG's stated policies prohibit consultants from sharing any nonpublic information about their employer or any public company, from violating any ethical or legal restrictions that apply to them, and from breaking any law, and the firm has built an extensive compliance infrastructure — expert screening, training and engagement terms — that it now markets as industry-leading. Compliance, in other words, became part of the product: institutional clients pay GLG partly to be able to show that expert research was gathered inside clear rules.
Ownership, investment and the withdrawn IPO
Private equity has financed GLG's growth at each stage. Bessemer Venture Partners invested in the firm — a $30 million round in 2004 is recorded in industry histories — and Silver Lake Partners invested $200 million in 2008 at a valuation reported at $875 million, making GLG one of the earliest companies described as a unicorn. SFW Capital Partners made a further strategic equity investment of $212 million in 2015. In October 2021 the firm filed to go public on Nasdaq under the symbol GLGX, reporting $628 million of revenue for the twelve months ended June 30, 2021, with Morgan Stanley, Goldman Sachs, BofA Securities, Barclays, Jefferies, Baird and William Blair lined up as joint bookrunners on a proposed $100 million offering. It withdrew the IPO in March 2022 as market conditions turned, and remains privately held.
Leadership
Mark Gerson remained a central figure as executive chairman after co-founding the firm. Alexander Saint-Amand led GLG as president and chief executive from its early years until 2018, when Paul Todd — previously head of eBay's Europe, Middle East and Africa business — succeeded him as chief executive. Postlethwaite first joined GLG's board while serving as chief executive of business information company Arizent, bringing experience from PIRA Energy Group and eight years at Thomson Reuters, and in July 2023 she succeeded Todd as chief executive. Under her leadership the company has emphasised client-centric product development and technology, including the AI-powered myGLG platform and a new San Francisco office in the Financial District at 595 Market Street, opened to serve West Coast technology, consulting and finance clients.
Social impact work
Alongside its commercial research, GLG operates a Social Impact Fellowship that provides learning resources and expertise to selected nonprofits at no cost, applying the same matching machinery to organisations that could not otherwise buy it. The firm has also offered pro bono support during crises, including services for organisations addressing the COVID-19 pandemic. Nonprofits appear on both sides of its business — as clients of the paid network in some cases, and as fellowship beneficiaries in others — reflecting the extent to which expert access, once an investor luxury, has become a general research utility.
Assessment
GLG's historical claim is unusually strong for a research company: it invented its category. The 1999 decision to sell conversations instead of guidebooks created the expert-network industry, and a quarter-century later GLG remains its largest operator, connecting more than a million experts to the investors, consultants and executives whose decisions depend on firsthand knowledge. Headquartered in New York City, with 22 offices across 12 countries and a compliance framework shaped by the industry's hardest scrutiny, GLG — a short name for the Gerson Lehrman Group, after its two founders — continues to define how professional research buys human expertise by the hour.
