Beachhead TAM (U.S.) — $12B

• ~95M new specialist visits/year (Fig 1.)
• ~60–75M new completed specialist visits/year are effectively patient-led bookings
• ~120-150M annual booking attempts (implied from completions ÷ baseline completion)
• $100 per booked new patient (booking-fee model, zocdoc.com)

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~120-150M annual booking attempts × $100 per new patient ≈ $12B–$15B

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Actual TAM (U.S.) — $25B+

• Expand from booking into the full specialty ai-native front door stack:
  • intake
  • benefits/OOP
  • prior auth
  • records
  • payments
  • patient engagement
• Expand from new visits into follow-ups and episodes (~420M specialist office visits/year) (cdc.gov)
• Expand buyers: payors (site-of-care), systems (capacity/leakage), PCPs (quality/closed-loop)

Beachhead TAM Math

In the U.S., the “moment after the PCP visit” is already enormous in completed specialty care. CDC’s 2018 NAMCS implies roughly 95M new patient specialist visits per year in office based settings.

A large share of those visits are effectively patient led. Based on NAMCS referral status mix plus real world scheduling behavior, we estimate ~60–75M of those completed new specialist visits involve journeys where the patient materially drives the booking.

Completed visits understate the true booking market because many attempts never convert. Health system benchmarks show only ~34.8% of referral scheduling attempts end in a documented completed appointment, and completion is meaningfully higher when staff actively schedules, so we use ~50% as a conservative baseline and ~80% as a with-`support benchmark.

If ~60–75M completions represent roughly half of attempts at baseline, that implies ~120M annual booking attempts. At ~$100 per booked new patient anchored to Zocdoc’s model, this beachhead is ~$12B–$15B U.S. TAM.

Figure 1. Specialist booking funnel splitting established vs new visits and highlighting where patients drive scheduling and where attempts drop off before a completed appointment.