David Karp

Founder of Tumblr; angel investor at independent

Reviewed Updated May 1, 2026

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Location New York, New York
Check Size Undisclosed (angel)
Last Verified Investment Splash (Series B) — Dec 14, 2016
Social @davidkarp
Stage Focus
seed series-a series-b
Sector Focus
consumer healthcare mobility marketing-tech

Background

David Karp was born July 6, 1986 in New York City 1. He attended The Bronx High School of Science for one year before leaving in 2001 to pursue homeschooling, an internship, and self-taught engineering 1. He began learning HTML in 1997 1.

At age 14, Karp started interning at Frederator Studios under animation industry veteran Fred Seibert, where he built the company’s first multi-user blogging platform and helped develop the Channel Frederator video network 2. He subsequently worked as head of product (and later CTO) for the New York-based parenting forum UrbanBaby, including a five-month stint in Tokyo while still a teenager 1 2. UrbanBaby was acquired by CNET in 2006; Karp used his proceeds to start a software consultancy called Davidville 1 2.

Tumblr launched in February 2007, built by Karp with engineer Marco Arment during a two-week gap between Davidville consulting contracts 1. The platform reached 75,000 users within two weeks of launch 1. In October 2007, Karp shut down the consultancy, renamed the company Tumblr, Inc., and raised a $750,000 Series A from Spark Capital and Union Square Ventures 1 3. Subsequent rounds came from Sequoia Capital (which led a 2010 round through partner Roelof Botha 4), Greylock Partners, Insight Venture Partners, Betaworks, and individual angels including Martín Varsavsky and Fred Seibert 3.

On May 20, 2013, Yahoo announced its acquisition of Tumblr for approximately $1.1 billion in cash 3. Karp remained CEO. On November 27, 2017, he announced his departure by year-end, citing “months of reflection on my personal ambitions” 5 6. He was succeeded by Jeff D’Onofrio, then Tumblr’s president and COO 5.

Karp joined the board of directors of Planned Parenthood in 2014 1. He has not, as of public reporting available through May 2026, founded a new operating company or joined a venture firm; his post-Tumblr public activity has been primarily as an independent angel investor.

Stated Thesis

Karp has not published a formal angel investing thesis. His public statements about product and founders, drawn from interviews during the Tumblr years, give the closest available signal of how he evaluates companies.

On building products for a market the existing tools missed: “I think there’s a market that wasn’t served by the existing tools” 7. On Tumblr’s founding hypothesis, he told TechCrunch in 2011: “These tools I just don’t think worked for most people. It’s a commitment, you need to sit down for an hour and hammer out a post” 8. He framed the same opportunity in product terms: “All blogs took the same form. I wanted something much more free-form, much less verbose” 8.

Sequoia Capital’s published founder page describes its 2010 first meeting with Karp as “the investor/entrepreneur equivalent of love at first sight” and credits him with understanding “his users and what he created; he didn’t just stumble upon it by accident” 4. Frederator’s Fred Seibert, who mentored Karp from age 14, has summarized his pattern as: “every product he created is something he wanted himself” 2.

These are operator-era statements. Karp has not given extensive on-the-record interviews about angel investing criteria, so they should be read as historical context rather than current investment thesis.

Inferred Thesis

Sample size caveat: only 3 angel investments are independently verifiable from contemporaneous press, plus 5 additional unconfirmed entries reported by CB Insights (8 total claimed) 9. This sample is too small to support sector or stage percentages. The inferred thesis below is qualitative.

The three verified deals — Superpedestrian (urban mobility / connected hardware, 2013), Sherpaa (digital primary care, 2014), and Splash (B2B event marketing software, 2016) — share several patterns:

  • Co-investor concentration on Spark Capital. All three verified rounds included Spark Capital, the firm whose partner Bijan Sabet led Tumblr’s Series A in 2007 3 10 11 12. Karp’s angel checks have most often appeared alongside the firm that backed him as a founder.
  • New York-based companies and consumer-adjacent founders. Sherpaa (Jay Parkinson, NYC) 13 and Splash (Ben Hindman, NYC) 11 are NYC startups; Superpedestrian (MIT spinout, Cambridge MA) is the geographic outlier 10 12. None are deep-tech enterprise infrastructure.
  • Single-founder or design-led companies with strong product opinions. Each portfolio company is associated with a charismatic individual founder shipping a strongly-opinionated consumer or prosumer product, not a team of enterprise-software veterans.
  • Cadence is sparse, not professional. The verified deals span 2013-2016 across roughly four years. Karp’s angel activity does not match the deal velocity of dedicated angel investors or solo GPs; he behaves more like a successful operator writing occasional checks for founders he believes in than as an active investor building a portfolio.
  • No publicly verified investment after the Splash 2016 Series B. CB Insights reports no further investments through May 2026, and his most recent verified portfolio event is the Cvent acquisition of Splash in September 2024 9.

Active investor signal: weak. A founder evaluating Karp as an angel today should treat him as a potentially dormant investor unless they have direct evidence of recent activity. The Splash exit in 2024 demonstrates a return event, not a new investment.

Portfolio

Company Year Stage Source
Superpedestrian 2013 Series A ($2.1M, alongside Spark Capital) 10 12
Sherpaa 2014 Series A ($4M, led by SoftBank Capital’s Josh Guttman; Karp invested ~$500K per WSJ) 13
Splash 2016 Series B ($7M, led by Ascent Venture Partners; Karp participated alongside Spark Capital, Lerer Hippeau, ScaleUP Ventures, Rus Yusupov) 11 14

CB Insights lists 8 total investments and 3 portfolio exits but most company names are paywalled; only Splash (most recent investment, December 14, 2016; acquired by Cvent September 4, 2024) is fully disclosed publicly 9. Pitchbook also maintains a portfolio profile 15 but content is gated. Independent press confirms only the three rows above.

In Their Own Words

On the founding insight that produced Tumblr (TechCrunch Founder Stories, February 2011):

“These tools I just don’t think worked for most people. It’s a commitment, you need to sit down for an hour and hammer out a post.” 8

“All blogs took the same form. I wanted something much more free-form, much less verbose.” 8

On differentiation from social-network competitors (same interview):

“They are not tools built for creative expression.” 8

On scaling decisions during Tumblr’s 2010 growth phase (.net magazine, issue 213, 2011):

“I wanted to do something different. I was determined not to compete with WordPress.” 7

“I think there’s a market that wasn’t served by the existing tools.” 7

From his November 27, 2017 farewell letter to Tumblr employees:

“After nearly 11 years, I’ve decided that 2017 will be my last year at Tumblr.” 6

“This team and place has been my family and home for most of my adult life.” 6

“my decision comes after months of reflection on my personal ambitions” 6

What Founders Say

No independently sourced founder testimonials about working with David Karp as an angel investor were found after dedicated searching. His angel checks have been small components of larger institutional rounds (typically led by Spark Capital, Ascent, or SoftBank), and portfolio founders’ public statements at funding announcements have generally credited their lead investors rather than individual angels.

Connections

  • Spark Capital — Bijan Sabet. Sabet led Tumblr’s Series A in October 2007 and served on the Tumblr board; Sabet was introduced to Karp by Fred Seibert in late 2006 2 3. Karp has since co-invested with Spark Capital in all three of his publicly verified angel deals (Superpedestrian, Sherpaa via Spark’s later participation, and Splash) 10 11.
  • Sequoia Capital — Roelof Botha. Botha led Sequoia’s 2010 investment in Tumblr; Sequoia’s published founder page describes the relationship in unusually warm terms 4.
  • Union Square Ventures — Fred Wilson. USV co-led Tumblr’s $750K Series A in October 2007 alongside Spark 3.
  • Betaworks — John Borthwick. Borthwick participated as an early angel and helped Karp structure Tumblr’s seed financing to retain control 2 3.
  • Frederator — Fred Seibert. Karp’s first professional mentor (from age 14); held a Tumblr board seat and was described in a 2013 MediaShift profile as “hands-off” and “a David ally” 2.
  • Planned Parenthood Federation of America — Board member (joined 2014) 1.

Sources

  1. David Karp — Wikipedia, accessed May 2026. https://en.wikipedia.org/wiki/David_Karp↩↩↩↩↩↩↩↩↩↩

  2. Mark Glaser, “Tumblr CEO David Karp’s Wild Ride from 14-Year-Old Intern to Multimillionaire,” MediaShift, May 2013, accessed May 2026. http://mediashift.org/2013/05/tumblr-ceo-david-karps-wild-ride-from-14-year-old-intern-to-multimillionaire/↩↩↩↩↩↩↩

  3. Tumblr — Wikipedia (funding history and acquisition), accessed May 2026. https://en.wikipedia.org/wiki/Tumblr↩↩↩↩↩↩↩

  4. Sequoia Capital, “David Karp” founder page, accessed May 2026. https://sequoiacap.com/founder/david-karp/↩↩↩

  5. Ingrid Lunden, “David Karp is leaving Tumblr by the end of the year,” TechCrunch, November 27, 2017, accessed May 2026. https://techcrunch.com/2017/11/27/david-karp-is-leaving-tumblr-by-the-end-of-the-year/↩↩

  6. Aric Jenkins, “David Karp Is Leaving Tumblr — Read His Retirement Letter Here,” Fortune, November 27, 2017, accessed May 2026. https://fortune.com/2017/11/27/tumblr-david-karp-leaving/↩↩↩↩

  7. Oliver Lindberg, “Interview with David Karp: the rise and rise of Tumblr” (originally .net magazine issue 213, 2011), Medium republication, accessed May 2026. https://medium.com/the-lindberg-interviews/interview-with-david-karp-the-rise-and-rise-of-tumblr-ed51085140cd↩↩↩

  8. Chris Dixon and Erick Schonfeld, “(Founder Stories) Why David Karp Started Tumblr: Blogs Don’t Work For Most People,” TechCrunch, February 21, 2011, accessed May 2026. https://techcrunch.com/2011/02/21/founder-stories-why-david-karp-started-tumblr-blogs-dont-work-for-most-people/↩↩↩↩↩

  9. David Karp — Portfolio Investments, CB Insights, accessed May 2026. https://www.cbinsights.com/investor/david-karp↩↩↩

  10. “Superpedestrian Emerges from Stealth with $2.1 Million in Funding from Spark Capital,” PR Newswire, October 21, 2013, accessed May 2026. https://www.prnewswire.com/news-releases/superpedestrian-emerges-from-stealth-with-21-million-in-funding-from-spark-capital-228616191.html↩↩↩↩

  11. Anthony Ha, “Splash transitions to B2B event marketing with $7M in new funding,” TechCrunch, December 14, 2016, accessed May 2026. https://techcrunch.com/2016/12/14/splash-pivots-to-b2b-event-marketing-with-7m-in-new-funding/↩↩↩↩

  12. “Superpedestrian Walks Off with $2.1M Series A,” VC News Daily, October 2013, accessed May 2026. https://vcnewsdaily.com/superpedestrian/venture-capital-funding/ftbznvpdxk↩↩↩

  13. Jay Parkinson, “Sherpaa raises a $4M Series A round led by Softbank,” personal blog, May 23, 2014, accessed May 2026. https://blog.jayparkinsonmd.com/2014/05/23/sherpaa-raises-a-4m-series-a-round-led-by/↩↩

  14. “Splash Announces $7 Million in Series B Funding,” PR Newswire, December 14, 2016, accessed May 2026. https://www.prnewswire.com/news-releases/splash-announces-7-million-in-series-b-funding-300378117.html↩

  15. David Karp investment portfolio, PitchBook, accessed May 2026. https://pitchbook.com/profiles/investor/106014-↩