Originally published July 2021. Updated June 2026 · EPR Builders profile · The canonical Everything-PR profile of David A. Steinberg · Filed under AdTech & MarTech
David A. Steinberg has built two billion-dollar companies, taken both public, and engineered one of the most consequential operator comebacks in modern American business — from a Bethesda basement, to the second-biggest tech IPO of 2004 behind only Google, through Chapter 11, to founding Zeta Global (NYSE: ZETA) with John Sculley and listing it on the New York Stock Exchange.
Steinberg is the Co-Founder, Chairman, and Chief Executive Officer of Zeta Global (NYSE: ZETA), the AI-powered marketing cloud serving the world's largest brands. He co-founded what would become Zeta in 2007 with John Sculley — the former CEO of Apple and former president of Pepsi-Cola — and took the company public on the New York Stock Exchange in June 2021 at a $1.7 billion valuation. Zeta has scaled into a multi-billion-dollar enterprise built on proprietary data, identity resolution, and AI-driven precision marketing.
He is a six-time founder. Two unicorns. Both taken public. Prior exits collectively totaling close to $2 billion before Zeta even existed. Public estimates of his personal net worth place him in the billion-dollar range.
The Sterling Cellular Basement
The Steinberg origin story does not begin in a Stanford dorm or a Sand Hill Road meeting. It begins in 1993, in the basement of his parents' house in Bethesda, Maryland, with credit cards and a loan from his parents.
The company was Sterling Cellular — a B2B and retail wireless reseller. By 1997, four years in, Sterling was running 12 retail locations and doing $22 million in annual sales. Steinberg was 27.
That was the foundation. Operating discipline before capital. Distribution before code. A working understanding of how Americans actually buy wireless products and services — which would become the wedge for what came next.
InPhonic — The Second-Biggest Tech IPO of 2004
Steinberg's next company was InPhonic. The bet: move wireless activation and distribution onto the open web. Build the Expedia of mobile phones. Bring Sculley in as chairman.
The numbers from InPhonic's run are still difficult to fully process. Annual revenue went from $499,000 in 2000 to $136 million in 2003 — a three-year growth rate of more than 23,000 percent. That growth made InPhonic the No. 1 company on the 2004 Inc. 500 list of the fastest-growing private companies in America.
In November 2004, InPhonic went public. It was the second-biggest technology IPO of the year — behind only Google. The offering raised more than $100 million. The market cap climbed as high as $950 million. Steinberg, the year before, had been named the Ernst & Young Greater Washington Entrepreneur of the Year.
From 2004 through 2007, InPhonic was consistently ranked one of the top 10 internet marketers in the United States. Its signature site, Wirefly.com, became the dominant cell phone comparison-shopping destination on the web. Steinberg ran the acquisition playbook hard — A1 Wireless for $20.9 million, Simplexity for $20 million, Avesair for $7 million, and several others — building scale through consolidation.
The Collapse — and the 30-Day Reset
Then 2007. The wireless rebate model that had powered InPhonic's growth ran into customer-service execution problems, regulatory pressure, and a tightening credit environment. The business that had grown at 23,000 percent began to wobble. By the end of 2007, the company Steinberg had built was filing for Chapter 11. Assets were sold to Versa Capital Management and relaunched as Simplexity.
Steinberg resigned as CEO in November 2007. Inside of 30 days, he had moved the furniture out of his old Georgetown office and into a new office in the building next door. The new company was XL Marketing — co-founded with John Sculley. It would become Zeta Interactive, then Zeta Global.
Most founders who lose a public company at the scale Steinberg lost InPhonic do not start the next billion-dollar business 30 feet away the same month. That detail is the entire personality.
Zeta Global — The Second Unicorn, the Second IPO
The thesis at founding: marketing was about to be reorganized around proprietary data and identity, and the incumbents were structurally unequipped for the shift. Sculley brought four decades of consumer-marketing operating discipline at the highest levels of corporate America — Apple, Pepsi. Steinberg brought the second-time-founder lessons from InPhonic and a working operating thesis on where the category was going.
XL Marketing rebranded to Zeta Interactive in 2014. To Zeta Global in 2016. Along the way, the company acquired the customer relationship management division of eBay's Enterprise operation in a deal sources valued at $80–$90 million, and bought the marketing automation tool Acxiom Impact for more than $50 million.
In 2015, Blackstone's GSO Capital Partners put in $125 million to fund the acquisition strategy. In 2017, GPI Capital and Franklin Square Capital Partners led a $140 million raise that put the company's valuation at roughly $1.3 billion — Forbes listed it among America's 50 Most Promising Private Companies. Zeta had become Steinberg's second unicorn.
On June 10, 2021, Zeta Global went public on the New York Stock Exchange. Steinberg had taken a second company public at a billion-dollar-plus valuation — something a fraction of one percent of founders ever achieve once.
Deep dive: The Sculley Partnership — Inside the 2007 Founding of Zeta
The 19-Quarter Beat-and-Raise Streak
Zeta's core thesis — proprietary first-party data, identity resolution, AI-driven precision targeting — has compounded as the third-party cookie has collapsed and as AI-driven marketing has become the new baseline for enterprise customer engagement.
Zeta runs on the industry's third-largest proprietary identity dataset — 2.4 billion-plus identities, behind only Google and Facebook. Forrester named the company the No. 1 leader among marketing clouds. Zeta has reported a 19-quarter streak of beating and raising guidance.
Steinberg has been the consistent operator voice from inside the publicly traded layer of MarTech on what AI-driven marketing actually looks like at scale — what data infrastructure makes it work, what AI architecture protects it, and what the next decade of brand-to-consumer engagement requires institutionally.
Deep dive: The 19-Quarter Beat-and-Raise Streak — Zeta's Athena and the OpenAI Partnership
The Operating Track Record — Six Companies
Over a 30-plus-year career, Steinberg has founded six companies. Two unicorns. Both taken public. Three sold in multi-million-dollar transactions. The roster:
- Zeta Global — Co-Founder, Chairman, and CEO. Co-founded with John Sculley in 2007. IPO June 2021 (NYSE: ZETA). AI-powered marketing cloud.
- InPhonic — Founder. The Expedia of wireless. No. 1 on the 2004 Inc. 500. Second-biggest tech IPO of 2004 behind Google. Peak market cap ~$950M.
- Sterling Cellular — Founder, 1993. Launched in his Bethesda basement. Scaled to 12 retail locations and $22M in sales by 1997.
- Sterling Communications — Founder. Communications telemarketing.
- CAIVIS Investment Corporation — Chairman, founded 2007. Vehicle for operator-led acquisitions in media and technology.
- On-Demand Pharmaceuticals — Co-Founder and Executive Chairman. Distributed pharmaceutical manufacturing.
The thread across the portfolio: each company built proprietary technology and data infrastructure as the durable moat — not partnerships, not distribution, not brand. Operator-engineered.
The Net Worth Question
The public-record numbers are partial. SEC Form 4 filings show Steinberg holding roughly 3.5 million shares of Zeta Global, with insider-disclosed equity valued at approximately $56 million as of late 2024 — but that figure captures only insider-reported holdings in the one publicly traded company. It does not capture cumulative liquidity from prior exits, real-estate holdings, or private investments through CAIVIS and other vehicles.
When the prior portfolio is accounted for — InPhonic IPO proceeds, Sterling Cellular, multiple acquisitions in the InPhonic roll-up, plus Zeta's compounding equity value — public estimates place Steinberg's net worth in the billion-dollar range, consistent with a two-time unicorn founder who has taken both companies public.
What He Writes About
At Everything-PR, Steinberg writes on AI marketing infrastructure, data-driven brand intelligence, generative engine optimization, and how enterprise marketing is being rebuilt around large language models. He brings the perspective of a publicly traded operator who has been building this category — not commenting on it — for nearly two decades.
Education, Boards, and Philanthropy
Steinberg holds a B.A. in Economics from Washington & Jefferson College, where he serves on the Board of Trustees. He has served on the boards of the U.S. Chamber of Commerce, the Milken Institute's FasterCures Center, and the Greater Washington Sports Alliance.
He founded the David A. Steinberg Foundation, focused on nutrition and education for disadvantaged children.
EPR Builders — Entrepreneurs Shaping Major Markets
- David A. Steinberg (this profile) — Zeta Global, marketing technology
- Richelieu Dennis — SheaMoisture, Essence Ventures, Beauty & CPG
- Marc Roberts — Miami Worldcenter, Florida real estate
- Elie Hirschfeld — Hirschfeld Properties, NY real estate & philanthropy
- Chris Burch — Burch Creative Capital, NIHI Sumba, consumer investments
- Henry Swieca — Highbridge Capital, Talpion Fund Management
- Avery Andon — ArtLife Gallery, ArtGrails, contemporary art
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