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The Secret to Slack's Early Success & $27 Billion Acquisition: A Conversation with Slack’s First CFO

The Secret to Slack's Early Success & $27 Billion Acquisition: A Conversation with Slack’s First CFO

Content Team
July 3, 2025
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We all know Slack today as the productivity & messaging app that has revolutionized the way we work. 

But how many of us actually know how Slack grew to become the global household name worth over $27 billion? 

In our fifth episode of the #CFOTalks Podcast, we had the great opportunity to speak with Allen Shim, former CFO of Slack. 

Joining as one of the first 20 employees at Slack, Allen has played an instrumental role in shaping the company’s growth since the beginning, past IPO and through acquisition.

In this episode, Allen shares

  • His insider journey while scaling Slack from 20 to a 2,500+ strong global team 
  • The hallmark of a strong CFO - CEO relationship at a hyper growth startup 
  • His framework for determining “public company readiness” on the path to IPO

Navigating the Reality of Public Company Readiness for Slack

“We discouraged the team from talking about IPO. All we talked about was PCR - Public Company Readiness. It wasn’t just about getting the company financials in order. We had to be able to run with a rhythm, predictability and a non-negotiable schedule. 

The culture that I was trying to promote early on was - this is where we are going and that’s why we're taking these steps today, not just trying to fix things for the moment. Giving people clarity on what was coming was valuable in allowing Slack to function well as a public company, beyond the direct listing itself.” 

The crucial role of trust in the CEO-CFO dynamic

“CFOs aren’t there to serve the CEO, they promote the needs of the company. It’s important to have a different perspective as you become a public company and represent other shareholders. The hallmark of a strong CEO-CFO relationship is trust, the ability to challenge and to create through some of that friction and tension. 

When trust is high, communication can be low. When trust is low, communication is high. When you really trust someone, the amount of times you need to check in with them or the nature of the check-ins is efficient.”

On the importance of approaching the path to IPO with a long term, sustainable view 

“When I joined YuMe, I saw the early stage of growth and helped it scale to a few hundred million in revenue. The life of a public company of that size and scale was very challenging. We understood what it meant to go public, but not what it meant to be a public company. 

The analogy I like to share all the time is that a wedding is different from a marriage. A wedding is cool, exciting and fun. Marriage is long-term, with a lot of blessings and amazing parts but also shared challenges. We underestimated the “marriage” element of being a public company. At that point, I was considering - knowing what I know now, can I bring my business acumen to do this again at Slack?

The road to going public at Slack took many years, we made a deliberate effort to prepare for the “marriage” and not the “wedding”. "

This blog is for general information only and does not constitute financial, legal, tax, or professional advice. Aspire’s services are subject to the terms outlined in our 'Terms of Service' and'Pricing'pages. We make no guarantees as to the accuracy, completeness, or timeliness of the content, and past results do not indicate future performance. Always consult a qualified professional before acting on any information provided.
Content Team
at Aspire is a society of seasoned writers & experts specialising in finance, technology and SaaS space. With 50+ years of collective experience, they help make business finance more profitable for readers. They write about finance tools, finance insights, industry trends, tactical guides to grow your business & also all things Aspire.
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