Stack Overflow Acquisition, Valuation, Funding & Investors

Stack Overflow was acquired by Prosus for $1.8B in June 2021.

Stack Overflow acquisition price

$1.8B

Acquired by Prosus · Jun 2021

Cumulative funding Stack Overflow raised

$135M

across 3 funding rounds

Key investors in Stack Overflow

  • Andreessen Horowitz
  • Index Ventures
  • Spark Capital
  • Union Square Ventures
  • Bezos Expeditions
  • GIC
  • Silver Lake
  • Times Bridge

Stack Overflow Overview

About Stack Overflow

Stack Overflow operates a public question-and-answer platform where developers and technologists create, review and share technical knowledge. The public site organizes questions by topic and uses voting, editing, reputation and moderation systems to surface useful answers. Stack Exchange, Inc. also sells enterprise knowledge-management products that let organizations build private, validated repositories for employees and artificial-intelligence systems. Those products include integrations, application interfaces and tools for governing internal knowledge. Revenue comes from enterprise subscriptions, advertising and related data or platform services. The company serves individual developers on its public network and business customers through its enterprise offering. A person affiliated with Stack Overflow participated as an angel in Flare's 2026 round, but Stack Overflow itself was not announced as a corporate investor.


Founded

2008

HQ

United StatesNew York City, NY

Status

Acquired

Customer focus

B2B & B2C

Revenue model

Advertising, Subscription

Valuation

$1.8B (acquired Jun 2021)

Stack Overflow Acquisition

Stack Overflow was acquired by Prosus for $1.8B on 2 June 2021.

Before the acquisition Stack Overflow had raised $135M across 3 funding rounds.

Stack Overflow acquisition details
AcquirerDateTypePrice
2 Jun 2021Strategic M&A$1.8B

Stack Overflow Funding History

Stack Overflow has raised a total of $135M across 3 funding rounds.

Stack Overflow's first fundraising round was a $10M Series C in June 2013. The most recent completed round was a $85M Series E in July 2020.

Stack Overflow funding rounds

Stack Overflow funding rounds
DateStageInvestorsRaisedDeal Summary
Jul 2020Series EGIC (lead); Silver Lake; Index Ventures; Spark Capital; Union Square Ventures; Andreessen Horowitz; Times Bridge$85MStack Overflow, the leading Q&A platform for developers visited by over 120 million people monthly, raised $85 million in its Series E funding round on July 28, 2020, led by GIC with participation from Silver Lake Waterman and existing investors Andreessen Horowitz, Index Ventures, Spark Capital, and Union Square Ventures. This brought total funding to $153 million. The capital was earmarked to accelerate Stack Overflow for Teams, its SaaS knowledge management and collaboration product launched in 2017, which had seen revenue double annually. The round followed a five-year gap since the prior raise in 2015, positioning Stack Overflow to invest in public community tools, moderation, and developer products amid symbiotic growth between its free Q&A site and enterprise offerings. Stack Overflow for Teams targeted enterprise needs for internal knowledge sharing, leveraging the public platform's vast expertise. Investors like GIC, a Singapore sovereign wealth fund with tech experience, joined to support expansion into new markets and product enhancements. The company emphasized long-term mission alignment with technologists building future applications.
Jan 2015Series DAndreessen Horowitz (lead); Index Ventures; Spark Capital; Union Square Ventures; Bezos Expeditions$40MStack Overflow, operated by Stack Exchange (now known as Stack Overflow), is a leading Q&A platform for professional and enthusiast programmers founded in 2008. The company raised $40 million in a Series D funding round in January 2015, led by Andreessen Horowitz, with participation from existing investors including Union Square Ventures, Spark Capital, Bezos Expeditions, and Index Ventures. This brought the total funding raised to $70 million at that time. The investment aimed to enhance platform capabilities, support new product development, and capitalize on its role as a key resource for over 26 million developers, serving as a talent hunting ground for more than 10,000 companies including Amazon and Microsoft. Chris Dixon from Andreessen Horowitz joined the board as an observer, highlighting Stack Overflow's status as the indispensable home for the world's programmers due to its community-driven model that prioritizes high-quality answers through voting and avoids opinionated or commercialized content. CEO Joel Spolsky emphasized the platform's design to make programmers' jobs easier by surfacing the best answers first and maintaining trust through editorial independence. This round followed prior financings: Series A ($6M in May 2010 led by Union Square Ventures), Series B ($12M in March 2011 led by Index Ventures and Spark Capital), and Series C ($10M in June 2013 led by Bezos Expeditions). The platform's growth was driven by network effects and the established audiences of founders Joel Spolsky and Jeff Atwood, positioning it strongly in the developer community amid a shortage of programming talent.
Jun 2013Series CBezos Expeditions (lead)$10MStack Overflow raised $10M in its Series C funding round in June 2013 led by Bezos Expeditions. The funding aimed to further develop the platform and expand its user base. Previous rounds included a $6M Series A in May 2010 led by Union Square Ventures and a $12M Series B in March 2011 led by Index Ventures and Spark Capital.

Who has invested in Stack Overflow?

8 investors have backed Stack Overflow across its funding rounds, including Andreessen Horowitz, Index Ventures, Spark Capital, Union Square Ventures, Bezos Expeditions and GIC.

Lead investors include GIC, Andreessen Horowitz and Bezos Expeditions.


Stack Overflow Investors

Investors in Stack Overflow by funding rounds participated
InvestorHQRoundsRoleFirst check
Index VenturesUnited KingdomLondon2ParticipantJan 2015
Spark CapitalUnited StatesSan Francisco, CA2ParticipantJan 2015
Union Square VenturesUnited StatesNew York City, NY2ParticipantJan 2015
Andreessen HorowitzUnited StatesSan Francisco, CA2LeadJan 2015
Bezos ExpeditionsUnited StatesMercer Island, WA2LeadJun 2013
Silver LakeUnited StatesSan Francisco, CA1ParticipantJul 2020

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Stack Overflow Competitors

Stack Overflow competitors include listed companies like Progress Software, C3.ai and Justsystems, and private ones like Bled Tech, CircleCI and LMArena.

Public and private companies comparable to Stack Overflow
CompanyHQStatusRevenueEBITDAValuationRevenue Multiple
Progress SoftwareUnited StatesUnited StatesPublicly listed$978M$302M$1.8B2.8x
C3.aiUnited StatesUnited StatesPublicly listed$250M($484M)$1.9B5.2x
Bled TechUnited KingdomLondonPrivate$96M-$1.7B17.7x
CircleCIUnited StatesSan Francisco, CAPrivate--$1.7B-
LMArenaUnited StatesSan Francisco, CAPrivate$30M-$1.7B56.7x
JustsystemsJapanJapanPublicly listed$326M$153M$2B3.7x

Stack Overflow Public Comps

Stack Overflow is no longer listed, but its public comps include Progress Software, C3.ai, Visual China Group, Xinhuanet, Ziff Davis, RUM Group, Sanoma, Justsystems, Trustpilot Group and New Guomai Digital.

Last FYEV/RevenueEV/EBITDA
RevenueEBITDALast FYLTM2027ELast FYLTM2027E
Progress Software$978M$302M3.0x2.8x9.7x7.3x
C3.ai$250M($484M)4.9x5.2x(2.5x)(7.5x)
Visual China Group$117M$21M14.1x14.9x76.9x36.0x
Xinhuanet$335M$66M4.5x4.6x22.8x24.9x
Ziff Davis$1.5B$335M0.8x0.9x3.5x3.2x
RUM Group$101M($78M)23.4x10.4x(30.3x)(47.6x)
Sanoma$1.5B$285M1.2x1.1x5.9x4.0x
Justsystems$326M$153M3.7x3.7x7.9x-

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Common questions about Stack Overflow

When was Stack Overflow founded?Stack Overflow was founded in 2008.
Where is Stack Overflow headquartered?Stack Overflow is headquartered in New York City, NY, United States.
Is Stack Overflow publicly listed?No, Stack Overflow was acquired by Prosus in June 2021.
Who acquired Stack Overflow?Stack Overflow was acquired by Prosus in June 2021.
How much was Stack Overflow acquired for?Stack Overflow was acquired for $1.8B in June 2021.
How much funding has Stack Overflow raised?Stack Overflow has raised $135M across 3 funding rounds.
What was Stack Overflow's last funding round?Stack Overflow's last funding round was a $85M Series E in July 2020, led by GIC.
Who are Stack Overflow's investors?Stack Overflow's investors include Index Ventures, Spark Capital, Union Square Ventures, Andreessen Horowitz, Bezos Expeditions, Silver Lake, GIC and Times Bridge.
Which companies are comparable to Stack Overflow?Companies comparable to Stack Overflow include Progress Software, C3.ai, Bled Tech, CircleCI, LMArena and Justsystems.

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