general code ltd / internal memodraft v2 · apr 2026
gatekeeper scenario · revised financial model
The three-SSP open-web lift, re-examined.
cohort
1.0M US desktop users
scope
open-web standard display
horizon
monthly, 2026 baseline
change from v1
cpm, fill, demand-destruction
01 / 11→ tl;dr
tl;dr03 revisions · 01 sign-flip
executive summary
The v1 model was directionally right, numerically generous.
finding 01 · pricing
$4.50 → $2.75
$4.50 is a PMP-inclusive blend; pure open-auction US desktop standard display clears closer to $2.50–3.00 in 2026.
finding 02 · fill
90% → 75%
Removing AdX destroys demand, not just redirects it. Google Ads SMB & DV360-locked spend has no OpenRTB path to the Big 3.
finding 03 · scenario d
+$1.77M → −$0.36M
Static-only creative under a Big-3-only regime destroys Big 3 revenue vs. the status quo. The purity play is self-defeating.
the new narrative
Moderate restriction (Scenario B — partial AdX retention) beats aggressive restriction (Scenarios C / D). The gatekeeper thesis is strongest when it disciplines the auction, not when it tries to replace Google demand.
Second-price theory: losing a ~40%-share bidder shaves clearing prices 20–35%.
CPM damage — Scenario D (additional)
−30%
−30%
Retained. Static creatives price as remnant; directionally right.
03 / 11→ baseline economics
baseline · before any restrictionmonetized US desktop open-web display
baseline economics
The $5.94M/mo pool at stake.
users
1.0M
US desktop
monetized imp / mo
2.16B
1,200 pv × 3 slots × 60%
blended cpm
$2.75
2026 open-auction
baseline pool / mo
$5.94M
gross display spend
pool distribution — before
participant
share
revenue / mo
Google AdX
40%
$2.376M
Big 3 SSPs (combined)
35%
$2.079M
↳ SSP 1 (42% of Big 3)
14.7%
$0.873M
↳ SSP 2 (33% of Big 3)
11.6%
$0.686M
↳ SSP 3 (25% of Big 3)
8.8%
$0.520M
Long-tail SSPs
25%
$1.485M
TOTAL
100%
$5.940M
what moves under restriction
key modelling assumption
The Big 3 absorb redirected volume subject to two frictions:
(1) fill retention — not all displaced demand has a path via OpenRTB; and
(2) CPM damage — fewer bidders → lower clearing prices.
Both are under-modelled in v1.
04 / 11→ scenario A
scenario AAdX unchanged · long tail removed
A
AdX unchanged, long tail removed.
Most benign case — the Big 3 simply inherit the long-tail slice. No fill or CPM damage.
big3 share60%fill100%cpm$2.75
incremental monthly lift · per SSP
SSP 1
+$0.481M
SSP 2
+$0.526M
SSP 3
+$0.478M
TOTAL
+$1.485M
revenue distribution — after
participant
rev / mo
Δ
AdX
$2.376M
—
Big 3 combined
$3.564M
+$1.485M
Long tail
$0
−$1.485M
TOTAL POOL
$5.940M
flat
interpretation
Zero-sum transfer from long tail to Big 3. This is the cleanest scenario — and the most politically achievable, since Google is untouched.
05 / 11→ scenario B
scenario BAdX 50% retained · long tail removed
B
AdX 50% retained.
The optimal case in v2. Big 3 absorb long tail + half of AdX volume; fill and CPM hold up because AdX still competes.
big3 share80%fill93%cpm$2.61 (−5%)
incremental monthly lift · per SSP
SSP 1
+$0.722M
SSP 2
+$0.741M
SSP 3
+$0.656M
TOTAL
+$2.119M
revenue distribution — after
participant
rev / mo
Δ
AdX (half)
$1.188M
−$1.188M
Big 3 combined
$4.198M
+$2.119M
Long tail
$0
−$1.485M
TOTAL POOL
$5.386M
−$0.554M
the winner under v2
The Big 3 gain more here than in C, because keeping AdX in the auction preserves bid density. The total pool shrinks, but the Big 3's slice grows faster.
06 / 11→ scenario C
scenario CBig 3 only · AdX & long tail removed
C
Big 3 only.
AdX fully removed. Demand destruction bites: Google-Ads & DV360-locked spend has no OpenRTB path forward.
big3 share100%fill75%cpm$2.06 (−25%)
incremental monthly lift · per SSP
SSP 1
+$0.397M
SSP 2
+$0.450M
SSP 3
+$0.416M
TOTAL
+$1.262M
revenue distribution — after
participant
rev / mo
Δ
AdX
$0
−$2.376M
Big 3 combined
$3.341M
+$1.262M
Long tail
$0
−$1.485M
TOTAL POOL
$3.341M
−$2.599M
counter-intuitive finding
Big 3 lift is lower in C than in B. Capturing 100% of nothing < capturing 80% of something. The pool contraction swamps the share gain.
07 / 11→ scenario D
scenario DBig 3 only + static-only creative
D
Big 3 only · static-only.
The purity play. Static creatives are remnant-tier; HTML5-native campaigns are disqualified. Demand collapses.
big3 share100%fill55%cpm$1.44 (−47.5%)
incremental monthly lift · per SSP
SSP 1
−$0.221M
SSP 2
−$0.103M
SSP 3
−$0.040M
TOTAL
−$0.364M
revenue distribution — after
participant
rev / mo
Δ
AdX
$0
−$2.376M
Big 3 combined
$1.715M
−$0.364M
Long tail
$0
−$1.485M
TOTAL POOL
$1.715M
−$4.225M
the aha
The purity version of the gatekeeper scenario is self-defeating. Even the intended beneficiaries (Big 3) lose revenue vs. the status quo. Static-only is a narrative, not a business case.
08 / 11→ v1 vs v2
sensitivityv1 model vs v2 model · total Big-3 lift
original vs revised
Same scenarios, different story.
scenario A delta
−48%
scenario B delta
−56%
scenario C delta
−73%
scenario D delta
sign flip
09 / 11→ what breaks the thesis
stress testwhat breaks the gatekeeper thesis
stress test · v2
The thesis survives — if three things hold.
must hold
Partial-AdX preservation is viable. The gatekeeper can meter AdX access rather than block it. A hard-block regime (C/D) is worse than a throttle regime (B).
OpenRTB paths absorb long-tail spend. If long-tail demand is also locked to its SSPs (some DSP seat economics), the zero-sum transfer in A doesn't happen.
No retaliatory Chrome / AdSense / PAIR response. Any of those degrading Big-3 auction quality closes the gap v2 still shows.
sensitivity — Scenario B Big-3 lift ($M)
baseline CPM \ fill
85%
90%
93%
97%
$2.25
+1.44
+1.62
+1.73
+1.88
$2.50
+1.60
+1.80
+1.93
+2.09
$2.61
+1.67
+1.88
+2.01
+2.18
$2.75
+1.76
+1.98
+2.12
+2.30
$3.00
+1.92
+2.16
+2.31
+2.51
reading this
Scenario B lift stays in +$1.4M to +$2.5M/mo across the full plausible range. Even at the pessimistic corner ($2.25 CPM, 85% fill), the Big 3 still gain +$1.44M/mo. The B-scenario thesis is robust; it's C and D that are fragile.
thesis-breaker
If the gatekeeper cannot preserve some AdX participation — i.e., if the only politically feasible version is "all or nothing" — then v2 implies the scenario collapses from a +$2M/mo transfer into either a +$1.3M/mo win (C) or a −$0.4M/mo loss (D).
10 / 11→ takeaways
takeawayswhat to do with this
conclusions
Four things to walk away with.
01 · the size of the prize
$1.5M – $2.1M / mo
Per 1M US desktop users, under realistic assumptions. Scales linearly with cohort size. Attractive, not transformative.
02 · optimal design
Throttle, don't block
Scenario B (50% AdX retained) outperforms C and D. Preserve bid density — the Big 3 earn more from a smaller, healthier auction than from a monopolised, broken one.
03 · creative restrictions are a tax
Don't touch HTML5
Any "static-only" rule removes the very campaigns that generate premium CPMs. Scenario D goes negative. The purity narrative is incompatible with the revenue narrative.
04 · what to model next
Competitive response
Google's reaction is not modelled. A Chrome-signal degradation or a PAIR/seller-side tightening could close >50% of the v2 lift. This is the next uncertainty to quantify.
— end —“Capturing 100% of nothing is less than capturing 80% of something.”gatekeeper v2