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CJ Gustafson

CJ Gustafson is a former tech CFO and the creator of Mostly Metrics, a finance newsletter for current and aspiring CFOs that reached 65,000+ subscribers and roughly $3M in annual revenue with no full-time employees. He started writing in December 2020 while running FP&A at a hyper-growth tech company, spent 18 months at fewer than 500 subscribers, then compounded into a multi-six-figure side hustle and ultimately a full-time media business. He sold PartsTech (where he served as CFO) in January 2025 and went full time on Mostly Media. He also hosts the Run the Numbers podcast (200+ episodes), runs the Looking for Leverage newsletter for PE-portco CFOs, and co-hosts Mostly Growth. The Rebooting called him “an N of one” — 80th-percentile CFO + 80th-percentile writer + 80th-percentile business sense, stacked.

Key Patterns

  • The first 18 months were single-digit views; the next two years went from 400 to 27,000 subs. The flat part of the curve was the curve
  • Owned a single phrase (“CAC”) via four months of nightly Twitter replies to get the first 1,000 subscribers
  • Productized $5K-$10K sponsored guest posts that bundle backlink, borrowed audience, and republished content into one deal
  • Sponsorships are quarterly minimums only, never discounted; “really fucking expensive or free” (Scott Galloway rule)
  • 90% of revenue from sponsorships, split 40/40/10/10 across newsletter ads, podcast ads, dinners, and reports
  • Writes for the “internal share,” not the like, and engineers each post against four named forwarding archetypes
  • Treats a $209K failed marketplace as the real-world MBA that produced both the newsletter and the CFO role

Origin and Career

Two Hundred Nine Thousand Lost on a Tourism Marketplace — The failed Hotel Tonight x OpenTable x ClassPass marketplace that funded everything after Eighteen Months at Four Hundred Subscribers — The invisible runway: writing into the abyss before compounding kicked in Writing His Way to CFO — The newsletter that put him on a VC firm’s radar and landed his first CFO role

Growth Levers

Owning CAC - Four Months of Nightly Twitter Replies — The first-1K-subs playbook of replying to every relevant Twitter post nightly The Triple Stack - Paid to Distribute His Own Writing — Paid guest posts that doubled as backlinks, borrowed audiences, and republished newsletter content The Four Sharing Archetypes - Write for the Forward — Designing every post around who would forward it and why Niches Are Larger Than You Think — 70% of his readers aren’t CFOs; positioning narrowly pulled in adjacent audiences

Voice and Positioning

Walter the Dog and the Freak Flag — Personality as the moat in an over-serious vertical; “you may have the recipe but not the ingredients” The N of One - 80th Percentile in Three Things — Skill-stacking as positioning: CFO + writer + business sense = a SKU of one

Monetization and Business

Quarterly-Only Sponsorships and I Never Discount Anything — Premium sponsorship pricing with 13-touch logic and renewal-protecting discount discipline Mostly Media at Three Million With No Full-Time Employees — The lean structural choice that beats a $330M-valued media company’s profitability

Backlinks