STRATEGYongoing80% confidence

Installed-Base Arbitrage

Enter a market whose biggest cost is customer acquisition — when you already own the customers.

Problem it solves

Breaking into a market dominated by entrenched players (a duopoly) without their per-customer economics.

Best for

Multi-vertical platforms with a large owned audience entering a CAC-heavy category.

Not ideal for

First-time entrants with no existing customer base or brand to leverage.

Overview

Why this framework exists

The biggest cost for DraftKings and FanDuel is acquiring customers. Fanatics already had direct relationships with 100M+ sports fans and a known brand, so its effective acquisition cost is near-zero for a huge installed base. That structural advantage funds a better value proposition rather than ad spend: Fan Cash (a currency earned on every bet and spendable across betting, tickets, merch, collectibles), plus 'free insurance' that removes an injured player from a parlay in the first quarter. The thesis: if the value prop is genuinely better and you didn't have to pay to acquire the customer, you can take share from a duopoly over time.

Core principles

4 total
  1. Attack a market where the incumbents' dominant cost is the thing you already have for free.
  2. Spend the structural advantage on a better product/value proposition, not on outspending incumbents on ads.
  3. A loyalty currency that is actually burned (not hoarded) recycles customers across all your verticals.
  4. Being the underdog against a duopoly is a feature — 'people telling us we have no chance, that's love language.'

Origin story

How this framework came to be

Used to justify the betting-and-gaming entry in 2021-2023. Fanatics reached ~7.5% US sports-betting share roughly 20 months in, versus FanDuel/DraftKings' combined ~75-80%, having bought only PointsBet (Sept 2023) for its trading platform rather than building share through paid acquisition.

Source

Traced to primary
Source · VIDEO
Michael Rubin on Building Fanatics Into a Billion-Dollar Empire (Boardroom cover story)
Boardroom (Rich Kleiman) · 2025
Open source →

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