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Trainer profile

Donnacha Aidan O'Brien

1,137 runners in the lifetime window · 237 individual horses
As at 4 Nov 2026 · KTB archive: 2005–present, updated daily
Non-runners: 8.2% of 267 declared in the last 365 days, counting all recorded withdrawals, including reserves. For context, a typical day across all racing ends with about 6.5% withdrawn (middle half 5.3–8.1% over 364 racing days). As at 4 Nov 2026.
Last runner 5 days ago 100% of runners on the flat
Last 5 seasons Lifetime (2020→)
from 1 Jan 2008 — the aggregate floor: every horse in the window has a complete captured career behind it
146–1,137
Wins / Runs
12.8%
Strike rate
n=1,137
425 (37%)
Placed
0.97
Fair A/E
n=1,137 · 0.81 incl. margin
−271.57
£1 level stake
n=1,137 at SP · −23.9%
£7.46m
Prize money (window)
Strike by season
11.5%
KTB Yard Profile

Sends out around 60 runners a season, almost all on the flat, winning with 13% of them — level with the margin-free market read across the lifetime window (Fair A/E 0.97). The edge shows sharpest with horses returning fresh: 17% off breaks of two months or more (151 runs).

Deterministic profile computed from 1,137 archived runs (lifetime window) · updated 4 Nov 2026
KTB at a glance Fresh horses: 17.2% 33.5% when favourite Gavin Ryan: 13.1% from 718 Claiming riders: 13.6% Sends off the favourite in 14% of races
The read

The record is strongest at Killarney (29.4%, n=34), Tipperary (26.7%, n=30) and Dundalk (AW) (18.1%, n=155) — all clear of the yard's 12.8% baseline. Horses returning fresh after 61+ days have been a positive signal at 17.2% (n=151, Fair A/E 1.30), but debutants struggle at 8.1% (n=222, Fair A/E 0.80). Gavin Ryan rides 63% of the entries and matches the yard's average almost exactly (13.1%, A/E 0.94). The yard also reads well on Standard (AW) going (17.7%, n=158). 31 Group and Graded wins sit in the archive record — the biggest prize the yard has landed: the Al Basti Equiworld, Dubai July Cup Stakes at Newmarket (Jul 2026, £453,680). The stable star of the record: Porta Fortuna (IRE) — 8 wins from 11 runs for the yard.

Written from the figures on this page — every claim carries its sample. Descriptive, not a tip.

Yard patterns

the angles behind the record · vs 12.8% baseline
Fresh · 61+ days off
17.2%+4.4
n=151 · A/E 1.30 · £1 −31.95
New recruits · first run for the yard
6.7%−6.1
n=15 · A/E 0.50 · £1 −12.90
Debutants · first career start
8.1%−4.7
n=222 · A/E 0.80 · £1 −108.22
First-time headgear · true-first definition
8.5%−4.3
n=94 · A/E 0.79 · £1 −6.17
Headgear returns · back on after a bare run
15.4%+2.6
n=13 · A/E 1.37 · £1 +4.00
When favourite
33.5%
n=155 · A/E 0.99 · £1 −30.20
Claiming riders · a claimer in the saddle
13.6%+0.8
n=258 · A/E 1.02 · £1 −23.45
Group / Graded races · pattern & listed
11%−1.8
n=283 · A/E 1.00 · £1 −60.40

Each tile is the record in that situation vs the 12.8% baseline — descriptive splits with the sample always shown, for you to weigh. Tiles under 30 runs render muted. Headgear figures use the true-first definition (first gear appearance in the captured career); returns are gear back on after a bare run. Claiming riders are runs where the booked rider carried a weight claim. Group / Graded covers pattern and listed races. The same beliefs, tested across every yard and every GB and Irish race since 2005: Racing myths.

Notable angles

vs their own baseline
At Killarney 29.4% vs 12.8% · n=34
At Tipperary 26.7% vs 12.8% · n=30
With Killian Leonard 2.4% vs 12.8% · n=41
At Dundalk (AW) 18.1% vs 12.8% · n=155
With debutants 8.1% vs 12.8% · n=222
On Standard (AW) going 17.7% vs 12.8% · n=158
Descriptive splits ranked by divergence × sample — insight, not instruction. Every angle carries its N; nothing under 30 runs qualifies. Rows within 2pts of the baseline appear only when the market-relative read (Fair A/E) diverges, and show it.

Record by conditions

same window as header

Race type

TypeRWSR£1
Flat 1,133 145 12.8% −279.57
Hurdle 4 1 25% +8.00

Going

GoingRWSR£1
Good 475 46 9.7% −212.05
Soft 250 32 12.8% −107.58
Standard (AW) 158 28 17.7% +38.65
Good to Soft 89 14 15.7% −10.34
Heavy 89 12 13.5% −30.80
Good to Firm 75 13 17.3% +27.25
Firm 1 1 100% +23.30

Courses

CourseRWSR£1
Curragh 238 21 8.8% −102.53
Leopardstown 159 16 10.1% −23.87
Dundalk (AW) 155 28 18.1% +41.65
Naas 109 13 11.9% −60.39
Cork 74 8 10.8% −32.15
Navan 59 10 16.9% −18.14
Gowran Park 48 7 14.6% −22.55
Killarney 34 10 29.4% +2.91
Tipperary 30 8 26.7% +12.76
Down Royal 26 2 7.7% −6.75
Fairyhouse 24 4 16.7% +3.50
Ascot 23 2 8.7% −12.50
Limerick 22 1 4.5% −20.47
Galway 19 2 10.5% −9.62
Listowel 18 1 5.6% −14.50

Class

ClassRWSR£1
Class 1 283 31 11% −60.40
Class 2 5 0 0% −5.00
Class 3 5 1 20% −1.00

Market position

In the bettingRWSRA/E£1
Favourite 180 53 29.4% 0.92 −51.70
2nd–3rd fav 330 55 16.7% 0.98 −74.27
4th–6th fav 382 31 8.1% 1.08 −47.90
7th+ in betting 245 7 2.9% 0.88 −97.70
Fair A/E per band is the tell: near 1.00 the market had it priced right; well above, the wins came where the market didn't expect them.

Rows below n=30 are shown faded — a small sample is a fact, not a trend. Every figure carries its N.

Horses trained

same window as header · most-raced first
HorseRWPlLast ran
Moon Daisy (IRE) 23 3 8 27 May 23
Zozimus (IRE)then David O'Meara 16 1 7 5 Nov 21
Emporio (IRE)then Joseph Patrick O'Brien 15 2 10 25 Mar 23
Kilmeaden (IRE)then Faye Bramley 14 2 6 26 Jun 26
Wodao (FR)then Jamie Osborne 14 2 6 24 Sep 23
Snowy Owl (IRE) 14 1 6 2 Aug 21
Comanche Brave (IRE) 13 5 9 13 Sep 26
Emperor Of The Sun (IRE)from A P O'Brien 13 1 4 2 Oct 21
Spinning Around (IRE) 12 2 5 4 Oct 26
Lady Doris (IRE) 12 2 4 21 Jun 25
Amusement (IRE) 12 1 4 12 Sep 23
April Showers (IRE) 12 1 5 5 Nov 21
Showing the 60 most-raced of the 237 horses sent out in this window — each ran at least 7 times. Horses with fewer runs aren't listed; search finds any horse since 2005. Runs, wins and places only: a strike rate or a return on a handful of runs is noise, so none is quoted per horse — each horse's full record is on its own page.
Where they came from · where they went next

Of the 60 horses listed, 2 arrived from another yard in our archive, most often from A P O'Brien (2); 58 had their first archived run for this yard.

12 have since run for another yard, most often for Joseph Patrick O'Brien (2); 48 have no later run for another yard in our archive.

Read from each listed horse's whole archived career (2005 onwards), not only this window, and counted over the horses listed above, not the whole string. “First archived run” means our archive holds nothing earlier, not that the horse was unraced. A horse with no later run elsewhere may still be here, be off the track, or have run somewhere our archive does not cover — none of that is asserted.

Current form

significance-gated

Last 14 days

Small sample
1 from 5
Only 5 runners in the last 14 days — too few to read against the baseline (gate: n≥15). The card states the sample and stays neutral.

When the yard fires

strike by month, lifetime
JFMAMJJASOND
25119151210181113112233
A flat yard: the season runs Mar–Oct. Muted months are small samples (under 30 runs) — read them with the caution they deserve.

Jockey bookings

same window · biggest samples first
Go-to riderGavin Ryan
63% of all rides
13.1% SR · A/E 0.94
RiderRWSR£1
Gavin Ryan 718 94 13.1% −250.21
Paddy Harnett 183 22 12% +11.41
Chris Hayes 58 8 13.8% −6.97
Killian Leonard 41 1 2.4% −24.00
Muted rows are under 30 rides and sit behind "Show all".

Career highlights

lifetime archive, 2020→
146
Archived wins
31
Pattern / graded wins
£7.46m
Prize money
2025
Best season · 28 wins
Comanche Brave (IRE) — Al Basti Equiworld, Dubai July Cup Stakes (Group 1) Newmarket · Jul 2026 · Group 1
£453,680
Porta Fortuna (IRE) — Coronation Stakes (Fillies' Group 1) (British Champions Stakes) (Rnd) Ascot · Jun 2024 · Group 1
£368,615
Fancy Blue (IRE) — Prix de Diane Longines (3yo Fillies) (Turf) Chantilly (FR) · Jul 2020 · Group 1
£326,569
Notable horses
Porta Fortuna (IRE) Comanche Brave (IRE) Moon Daisy (IRE) Shale (IRE) Happy Pharoah (IRE) Havana Anna (GB)

Sires in the string

progeny record · win % by ground and trip
Galileo (IRE) 11% · 19–172
Progeny have won 14.5% of 18,200 runs since 2008 (1,776 horses). Strongest over 6f – 7f (all codes): 18.2% from 1,383. Weakest over 2m5f – 3m (all codes): 9.4% from 890.
Australia (GB) 13.4% · 13–97
Progeny have won 11.1% of 5,672 runs since 2018 (566 horses). Weakest over 2m5f – 3m (all codes): 6.5% from 108.
Ten Sovereigns (IRE) 16.9% · 13–77
Progeny have won 10.9% of 1,605 runs since 2023 (244 horses). Strongest at trips under 6f (all codes): 17% from 159. Weakest over 1m2f – 1m4f (all codes): 7.4% from 149.
No Nay Never (USA) 10.7% · 8–75
Progeny have won 12.1% of 6,358 runs since 2018 (708 horses). Weakest on Good to Soft going: 9.1% from 618. Weakest over 1m5f – 2m (all codes): 7.6% from 185.
Wootton Bassett (GB) 17.4% · 12–69
Progeny have won 13% of 5,687 runs since 2015 (790 horses). Strongest at trips under 6f (all codes): 16% from 162.
Churchill (IRE) 14.7% · 10–68
Progeny have won 11% of 4,837 runs since 2021 (462 horses).
Top line: the yard's own record with each sire's runners (win %, wins–runs), same window as the header; faded under 30 runs. Beneath it: every run by that sire's progeny in our archive since 2008, as at 4 Nov 2026 — what they have done, not a forecast. A going or a distance is named only where at least 100 progeny runs sit 3 or more points from the sire's own win rate. Distance bands cover Flat and jumps together.

The record

latest 50 of 1,137 · newest first

The latest 50 of 1,137 archived runners, newest first. The full record runs from 10 January 2020 to 30 October 2026.

DateCourseHorseRaceFinishSP
30 Oct 26 Dundalk (AW) (IRE) Lookingforarainbow (USA)J: Paddy Harnett Book Online At DundalkStadium.com Maiden8f · Standard · 14 ran 2nd 6/5F
28 Oct 26 Dundalk (AW) (IRE) Little Miss Muffet (IRE)J: Paddy Harnett Irishinjuredjockeys.com Fillies Maiden7f · Standard · 14 ran 1st 12/1
23 Oct 26 Dundalk (AW) (IRE) Might Just Be (IRE)J: Shane Foley Irish EBF Median Sires Series Maiden (Smullen Series)8f · Standard · 14 ran 11th 7/1
23 Oct 26 Dundalk (AW) (IRE) Final Ascent (USA)J: Paddy Harnett Irish EBF Median Sires Series Maiden (Smullen Series)8f · Standard · 14 ran 2nd 14/1
23 Oct 26 Dundalk (AW) (IRE) Near Perfection (IRE)J: Paddy Harnett Book Online At DundalkStadium.com Fillies Optional Claiming Race7f · Standard · 9 ran 2nd 9/2
20 Oct 26 Curragh (IRE) Isle Of Capri (IRE)J: Gavin Ryan Staffordstown Stud Stakes (Group 3)Class 1 · 8f · Yielding · 11 ran 4th 18/1
17 Oct 26 Leopardstown (IRE) Maathoor (IRE)J: Chris Hayes Irish Stallion Farms EBF (C & G) Maiden7f · Good · 12 ran 3rd 33/1
17 Oct 26 Leopardstown (IRE) Miss Hong Kong (IRE)J: Gavin Ryan Irish Stallion Farms EBF Laidlaw Cup Fillies Maiden7f · Good · 13 ran 3rd 5/1
16 Oct 26 Dundalk (AW) (IRE) Hip Hop Chrissy (IRE)J: Paddy Harnett James Crowe 1 Year Memorial Nursery Handicap7f · Standard · 13 ran 6th 10/1
11 Oct 26 Naas (IRE) Glyfada (IRE)J: Gavin Ryan Irish Stallion Farms EBF Garnet Stakes (Listed)Class 1 · 8f · Soft · 16 ran 3rd 8/1
09 Oct 26 Dundalk (AW) (IRE) Final Ascent (USA)J: Gavin Ryan Irish EBF Median Sires Series (C & G) Maiden7f · Standard · 14 ran 4th 9/2
09 Oct 26 Dundalk (AW) (IRE) Madam Sweetie Pie (USA)J: Chris Hayes Irish EBF Median Sires Series Fillies Maiden7f · Standard · 14 ran 12th 14/1
09 Oct 26 Dundalk (AW) (IRE) Sake Nights (GB)J: Gavin Ryan Irish EBF Median Sires Series Fillies Maiden7f · Standard · 14 ran 6th 11/1
08 Oct 26 Thurles (IRE) Yogini (IRE)J: Gavin Ryan www.thurlesraces.ie Maiden16.5f · Yielding To Soft · 9 ran 6th 7/1
08 Oct 26 Thurles (IRE) Abiding (IRE)J: Gavin Ryan Irish Stallion Farms EBF Fillies Maiden8.5f · Good To Yielding · 10 ran 7th 12/1
05 Oct 26 Killarney (IRE) Shaihaan (IRE)J: Chris Hayes Irish Stallion Farms EBF Navigation Stakes (Listed)Class 1 · 11f · Soft · 8 ran 1st 3/1F
05 Oct 26 Killarney (IRE) Forthethrillofit (IRE)J: Gavin Ryan Irish Stallion Farms EBF Maiden8f · Yielding To Soft · 12 ran 8th 100/1
04 Oct 26 Curragh (IRE) Spinning Around (IRE)J: Gavin Ryan Hailey Equine Irish EBF Brigid's Pastures Stakes (Listed)Class 1 · 6f · Soft · 16 ran 7th 10/1
03 Oct 26 Ascot Josh's Joy (IRE)J: Jason Watson Betmgm British Ebf October Stakes (Listed Race)Class 1 · 7f · Good To Firm · 12 ran 4th 12/1
02 Oct 26 Dundalk (AW) (IRE) Chosen One (IRE)J: Sadhbh Tormey BAR 1 Betting 'Best Odds Guaranteed Overnight' Maiden7f · Standard · 13 ran 7th 20/1

Drawn from the whole archive (2005 onwards), so it can include runs outside the window the header statistics cover. Non-runners are not listed. A finish shown in letters is a non-completion (F fell · UR unseated · PU pulled up · BD brought down).

KTB’s figures

the forward record · since 5 Oct 2026

KTB’s figures on this yard’s runners since 5 Oct 2026: the KTB Selection in 1 run (won 1) · top-rated on KTB Rating in 1 run (won 0) · to 17 Oct 2026.

Each pick was a KTB figure’s choice before the off — the published KTB Selection, the top-rated horse on KTB Rating, the fastest on KTB Speed — settled against the result the next morning and never worked out again; “did not run” is counted apart. GB and Irish races only. A record of weeks so far: read it as a count, not a verdict.

Quick answers

What is Donnacha Aidan O'Brien's strike rate?
Donnacha Aidan O'Brien has won 146 of 1,137 runners since 2008, a strike rate of 12.8% (as at 4 November 2026). Figures are computed from our own results archive.
Which course does Donnacha Aidan O'Brien do best at?
Killarney by strike rate: 10 wins from 34 runners (29.4%) since 2008. Read from the 15 courses with the most runners on the same basis, and only those with at least 30 — a small sample cannot top the list, and a rarely-visited course is not in the comparison.
Who rides most for Donnacha Aidan O'Brien?
Gavin Ryan, with 718 runners since 2008 — 63% of the total. That pairing has won 94 (13.1%).
Is Donnacha Aidan O'Brien in form?
Too few runners in the last 14 days to read — 5 runners, which is not a sample we will draw a conclusion from.
What is Donnacha Aidan O'Brien's Fair A/E?
0.97, from 1,137 runners with a computed fair probability since 2008. Fair A/E compares actual wins with a margin-stripped market expectation, so 1.00 is par: above it the wins came at bigger prices than the margin-free market implied, below it they did not.
Fair A/E compares wins with a margin-stripped market expectation. Favourite-heavy samples — top yards, leading riders — naturally read a few points warm, so 1.05 means "beat the margin-free market read", not "the market underrates this by 5%". Three sample sizes are reported and never blended: runs (n), the ROI basis (n at SP), and the fair-A/E basis (n with a computed fair probability).

Strike rate is wins over all runs (n). ROI is £1 level stakes at SP over runs with a parseable price (n at SP). Fair A/E is wins over margin-stripped market expectation, over runs with a computed fair probability (n fair). The three Ns can legitimately differ and are always shown. Figures as at 4 November 2026, computed from our own results archive (2005 onwards; aggregates from 2008).