Aon plc Class A Ordinary Shares (Ireland) vs Marsh
WatchlistAON / MRSHPrices through Oct 22, 2026
Why these are rivals: #1 and #3 by market value ($90B vs $61B) in Nasdaq's "Specialty Insurers" industry; SEC SIC 6411 / 6411 (same major group); #1 and #3 by market value ($90B vs $61B) with SEC SIC 6411 (Insurance Agents, Brokers & Service).
Rivals, but right now the price gap does not have a measured habit of closing, so there is no paper idea, whatever the gap.
- Mean reversion: ADF t-statistic of the spread: 0.57 (needs <= -2.873 (5% critical value))
- Speed: half-life of the spread, sessions: no mean reversion measured (needs <= 63)
Business leadership
MRSH is the larger business
Annual revenue reported to the SEC. Scale, not market share.
| Year | AON | MRSH | Larger |
|---|---|---|---|
| 2025 | $17.2B | $27.0B | MRSH |
| 2024 | $15.7B | $24.5B | MRSH |
| 2023 | $13.4B | $22.7B | MRSH |
| 2022 | $12.5B | $20.7B | MRSH |
| 2021 | $12.2B | $19.8B | MRSH |
| 2020 | $11.1B | $17.2B | MRSH |
MRSH led in every year with figures for both. Market value: AON $61.5B, MRSH $89.6B.
Stock leadership
MRSH is ahead now
Measured against the pair's own last 252 trading days.
MRSH leads AON by 3.01 standard deviations: +20.6% over its usual price ratio. 1 lead switch in the last year.
| Price change | 3 mo | 6 mo | 12 mo |
|---|---|---|---|
| AON | -15.2% | -5.2% | -10.7% |
| MRSH | +10.3% | +14.5% | +5.5% |
Relationship
Not a measured twin today
Only these tests can make a pair tradable on paper.
- Pass
- Aligned sessions: 2521 (needs >= 254)
- Pass
- Co-movement: daily return correlation, 252 sessions: 0.79 (needs >= 0.60)
- Fail
- Mean reversion: ADF t-statistic of the spread: 0.57 (needs <= -2.873 (5% critical value))
- Fail
- Speed: half-life of the spread, sessions: no mean reversion measured (needs <= 63)
- Data
- Both stocks current
The twins over two years
Prices side by side, and the gap between them
AON Aon plc Class A Ordinary Shares (Ireland) MRSH MarshPrice index, 100 = 2024-10-18. Tint = which stock is ahead of the pair's usual 1-year relationship (z beyond +/-0.5).
Spread z-score: AON relative to MRSH, against the 252 sessions before each day. Above 0: AON ahead; below 0: MRSH ahead. Lines at +/-2 (idea) and +/-4 (stop).
Data table (504 sessions)
| Date | AON index | MRSH index | z | Ahead |
|---|---|---|---|---|
| 2026-10-22 | 85.72 | 88.70 | -3.01 | MRSH ahead |
| 2026-10-21 | 82.24 | 84.82 | -3.02 | MRSH ahead |
| 2026-10-20 | 82.90 | 85.13 | -3.01 | MRSH ahead |
| 2026-10-19 | 80.95 | 83.90 | -3.24 | MRSH ahead |
| 2026-10-16 | 81.73 | 83.84 | -3.12 | MRSH ahead |
| 2026-10-15 | 80.13 | 83.03 | -3.37 | MRSH ahead |
| 2026-10-14 | 76.93 | 79.41 | -3.37 | MRSH ahead |
| 2026-10-13 | 76.75 | 78.79 | -3.34 | MRSH ahead |
| 2026-10-12 | 76.77 | 78.58 | -3.36 | MRSH ahead |
| 2026-10-09 | 76.40 | 78.23 | -3.45 | MRSH ahead |
| 2026-10-08 | 77.42 | 78.64 | -3.38 | MRSH ahead |
| 2026-10-07 | 75.57 | 77.30 | -3.62 | MRSH ahead |
| 2026-10-06 | 76.55 | 76.44 | -3.21 | MRSH ahead |
| 2026-10-05 | 76.01 | 75.86 | -3.28 | MRSH ahead |
| 2026-10-02 | 75.28 | 75.70 | -3.52 | MRSH ahead |
| 2026-10-01 | 77.10 | 76.49 | -3.30 | MRSH ahead |
| 2026-09-30 | 77.33 | 75.99 | -3.16 | MRSH ahead |
| 2026-09-29 | 77.08 | 75.86 | -3.25 | MRSH ahead |
| 2026-09-28 | 76.02 | 75.24 | -3.46 | MRSH ahead |
| 2026-09-25 | 77.67 | 76.17 | -3.32 | MRSH ahead |
| 2026-09-24 | 77.14 | 75.64 | -3.39 | MRSH ahead |
| 2026-09-23 | 78.67 | 75.84 | -3.04 | MRSH ahead |
| 2026-09-22 | 79.93 | 75.67 | -2.64 | MRSH ahead |
| 2026-09-21 | 81.25 | 76.88 | -2.67 | MRSH ahead |
| 2026-09-18 | 82.60 | 77.90 | -2.63 | MRSH ahead |
| 2026-09-17 | 82.71 | 77.71 | -2.57 | MRSH ahead |
| 2026-09-16 | 83.97 | 78.68 | -2.53 | MRSH ahead |
| 2026-09-15 | 85.12 | 80.01 | -2.66 | MRSH ahead |
| 2026-09-14 | 87.04 | 80.31 | -2.21 | MRSH ahead |
| 2026-09-11 | 84.57 | 78.75 | -2.48 | MRSH ahead |
| 2026-09-10 | 85.99 | 78.91 | -2.11 | MRSH ahead |
| 2026-09-09 | 85.13 | 78.71 | -2.34 | MRSH ahead |
| 2026-09-08 | 88.23 | 80.35 | -1.95 | MRSH ahead |
| 2026-09-04 | 90.27 | 82.68 | -2.12 | MRSH ahead |
| 2026-09-03 | 91.36 | 83.89 | -2.21 | MRSH ahead |
| 2026-09-02 | 92.44 | 83.61 | -1.81 | MRSH ahead |
| 2026-09-01 | 91.16 | 83.50 | -2.17 | MRSH ahead |
| 2026-08-31 | 89.83 | 84.48 | -2.94 | MRSH ahead |
| 2026-08-28 | 99.29 | 85.75 | -0.55 | MRSH ahead |
| 2026-08-27 | 97.66 | 84.57 | -0.63 | MRSH ahead |
| 2026-08-26 | 98.90 | 86.02 | -0.74 | MRSH ahead |
| 2026-08-25 | 99.13 | 86.09 | -0.69 | MRSH ahead |
| 2026-08-24 | 100.33 | 86.65 | -0.54 | MRSH ahead |
| 2026-08-21 | 99.21 | 85.47 | -0.46 | near the usual relationship |
| 2026-08-20 | 98.32 | 84.67 | -0.44 | near the usual relationship |
| 2026-08-19 | 97.35 | 84.22 | -0.56 | MRSH ahead |
| 2026-08-18 | 95.88 | 82.96 | -0.55 | MRSH ahead |
| 2026-08-17 | 97.01 | 82.00 | +0.08 | near the usual relationship |
| 2026-08-14 | 99.41 | 83.60 | +0.22 | near the usual relationship |
| 2026-08-13 | 99.76 | 83.99 | +0.20 | near the usual relationship |
| 2026-08-12 | 98.44 | 84.06 | -0.18 | near the usual relationship |
| 2026-08-11 | 99.59 | 85.13 | -0.20 | near the usual relationship |
| 2026-08-10 | 99.73 | 84.92 | -0.09 | near the usual relationship |
| 2026-08-07 | 100.10 | 85.31 | -0.11 | near the usual relationship |
| 2026-08-06 | 100.79 | 86.04 | -0.15 | near the usual relationship |
| 2026-08-05 | 100.57 | 85.23 | +0.05 | near the usual relationship |
| 2026-08-04 | 99.64 | 85.22 | -0.19 | near the usual relationship |
| 2026-08-03 | 99.92 | 85.84 | -0.30 | near the usual relationship |
| 2026-07-31 | 100.73 | 84.43 | +0.34 | near the usual relationship |
| 2026-07-30 | 102.41 | 85.24 | +0.53 | AON ahead |
| 2026-07-29 | 105.37 | 87.95 | +0.46 | near the usual relationship |
| 2026-07-28 | 106.52 | 85.55 | +1.46 | AON ahead |
| 2026-07-27 | 102.58 | 81.59 | +1.72 | AON ahead |
| 2026-07-24 | 101.05 | 80.45 | +1.70 | AON ahead |
| 2026-07-23 | 99.40 | 78.52 | +1.90 | AON ahead |
| 2026-07-22 | 98.44 | 78.34 | +1.72 | AON ahead |
| 2026-07-21 | 100.41 | 80.83 | +1.43 | AON ahead |
| 2026-07-20 | 101.36 | 81.06 | +1.60 | AON ahead |
| 2026-07-17 | 102.59 | 81.09 | +1.89 | AON ahead |
| 2026-07-16 | 102.99 | 81.08 | +1.99 | AON ahead |
| 2026-07-15 | 99.22 | 78.44 | +1.90 | AON ahead |
| 2026-07-14 | 100.27 | 79.25 | +1.91 | AON ahead |
| 2026-07-13 | 102.63 | 80.80 | +2.02 | AON ahead |
| 2026-07-10 | 99.72 | 79.37 | +1.76 | AON ahead |
| 2026-07-09 | 99.34 | 79.68 | +1.58 | AON ahead |
| 2026-07-08 | 99.88 | 79.70 | +1.71 | AON ahead |
| 2026-07-07 | 100.53 | 79.23 | +2.00 | AON ahead |
| 2026-07-06 | 99.72 | 77.78 | +2.25 | AON ahead |
| 2026-07-02 | 99.87 | 79.47 | +1.79 | AON ahead |
| 2026-07-01 | 95.99 | 76.62 | +1.72 | AON ahead |
| 2026-06-30 | 92.67 | 74.19 | +1.66 | AON ahead |
| 2026-06-29 | 91.52 | 74.21 | +1.37 | AON ahead |
| 2026-06-26 | 91.83 | 75.24 | +1.15 | AON ahead |
| 2026-06-25 | 88.27 | 72.21 | +1.18 | AON ahead |
| 2026-06-24 | 90.93 | 73.87 | +1.34 | AON ahead |
| 2026-06-23 | 89.61 | 72.93 | +1.30 | AON ahead |
| 2026-06-22 | 87.62 | 71.27 | +1.32 | AON ahead |
| 2026-06-18 | 88.77 | 72.29 | +1.29 | AON ahead |
| 2026-06-17 | 91.27 | 73.10 | +1.65 | AON ahead |
| 2026-06-16 | 92.60 | 74.24 | +1.63 | AON ahead |
| 2026-06-15 | 92.06 | 73.97 | +1.59 | AON ahead |
| 2026-06-12 | 93.68 | 75.08 | +1.64 | AON ahead |
| 2026-06-11 | 93.64 | 74.85 | +1.70 | AON ahead |
| 2026-06-10 | 93.97 | 74.40 | +1.89 | AON ahead |
| 2026-06-09 | 92.64 | 73.68 | +1.81 | AON ahead |
| 2026-06-08 | 91.04 | 72.34 | +1.84 | AON ahead |
| 2026-06-05 | 91.79 | 73.64 | +1.65 | AON ahead |
| 2026-06-04 | 90.03 | 71.78 | +1.78 | AON ahead |
| 2026-06-03 | 88.17 | 70.03 | +1.86 | AON ahead |
| 2026-06-02 | 88.81 | 71.84 | +1.51 | AON ahead |
| 2026-06-01 | 89.52 | 72.35 | +1.53 | AON ahead |
| 2026-05-29 | 88.30 | 71.21 | +1.57 | AON ahead |
| 2026-05-28 | 88.93 | 71.01 | +1.76 | AON ahead |
| 2026-05-27 | 89.00 | 71.48 | +1.65 | AON ahead |
| 2026-05-26 | 89.20 | 72.10 | +1.54 | AON ahead |
| 2026-05-22 | 90.74 | 73.05 | +1.61 | AON ahead |
| 2026-05-21 | 90.58 | 73.50 | +1.47 | AON ahead |
| 2026-05-20 | 89.72 | 72.72 | +1.50 | AON ahead |
| 2026-05-19 | 90.43 | 73.92 | +1.35 | AON ahead |
| 2026-05-18 | 91.24 | 73.88 | +1.52 | AON ahead |
| 2026-05-15 | 88.63 | 71.69 | +1.55 | AON ahead |
| 2026-05-14 | 88.12 | 71.23 | +1.57 | AON ahead |
| 2026-05-13 | 86.86 | 70.84 | +1.42 | AON ahead |
| 2026-05-12 | 88.38 | 72.73 | +1.27 | AON ahead |
| 2026-05-11 | 87.19 | 71.92 | +1.23 | AON ahead |
| 2026-05-08 | 87.39 | 72.67 | +1.10 | AON ahead |
| 2026-05-07 | 87.61 | 73.90 | +0.86 | AON ahead |
| 2026-05-06 | 86.13 | 72.95 | +0.80 | AON ahead |
| 2026-05-05 | 87.88 | 74.45 | +0.80 | AON ahead |
| 2026-05-04 | 87.98 | 74.72 | +0.77 | AON ahead |
| 2026-05-01 | 87.03 | 73.97 | +0.76 | AON ahead |
| 2026-04-30 | 87.07 | 74.65 | +0.63 | AON ahead |
| 2026-04-29 | 90.10 | 76.04 | +0.88 | AON ahead |
| 2026-04-28 | 89.87 | 76.03 | +0.85 | AON ahead |
| 2026-04-27 | 90.46 | 75.74 | +1.02 | AON ahead |
| 2026-04-24 | 89.72 | 75.71 | +0.90 | AON ahead |
| 2026-04-23 | 90.40 | 77.45 | +0.67 | AON ahead |
| 2026-04-22 | 91.32 | 78.12 | +0.70 | AON ahead |
| 2026-04-21 | 93.68 | 79.68 | +0.80 | AON ahead |
| 2026-04-20 | 92.74 | 77.71 | +1.04 | AON ahead |
| 2026-04-17 | 92.70 | 78.25 | +0.93 | AON ahead |
| 2026-04-16 | 93.69 | 81.27 | +0.52 | AON ahead |
| 2026-04-15 | 91.66 | 77.85 | +0.85 | AON ahead |
| 2026-04-14 | 90.25 | 76.94 | +0.80 | AON ahead |
| 2026-04-13 | 90.91 | 77.25 | +0.85 | AON ahead |
| 2026-04-10 | 87.33 | 74.85 | +0.73 | AON ahead |
| 2026-04-09 | 90.91 | 77.07 | +0.90 | AON ahead |
| 2026-04-08 | 92.13 | 78.26 | +0.88 | AON ahead |
| 2026-04-07 | 90.09 | 76.85 | +0.82 | AON ahead |
| 2026-04-06 | 91.13 | 77.82 | +0.81 | AON ahead |
| 2026-04-02 | 90.28 | 77.72 | +0.70 | AON ahead |
| 2026-04-01 | 89.78 | 76.50 | +0.86 | AON ahead |
| 2026-03-31 | 90.18 | 77.21 | +0.79 | AON ahead |
| 2026-03-30 | 90.54 | 77.77 | +0.75 | AON ahead |
| 2026-03-27 | 87.63 | 75.30 | +0.75 | AON ahead |
| 2026-03-26 | 90.46 | 77.51 | +0.80 | AON ahead |
| 2026-03-25 | 89.81 | 77.54 | +0.69 | AON ahead |
| 2026-03-24 | 91.37 | 77.05 | +1.05 | AON ahead |
| 2026-03-23 | 91.07 | 77.39 | +0.95 | AON ahead |
| 2026-03-20 | 90.98 | 78.55 | +0.71 | AON ahead |
| 2026-03-19 | 88.56 | 76.07 | +0.79 | AON ahead |
| 2026-03-18 | 88.81 | 76.12 | +0.83 | AON ahead |
| 2026-03-17 | 89.73 | 76.53 | +0.91 | AON ahead |
| 2026-03-16 | 91.29 | 77.34 | +1.02 | AON ahead |
| 2026-03-13 | 89.80 | 76.63 | +0.92 | AON ahead |
| 2026-03-12 | 88.26 | 76.06 | +0.77 | AON ahead |
| 2026-03-11 | 88.54 | 77.44 | +0.55 | AON ahead |
| 2026-03-10 | 89.67 | 77.45 | +0.75 | AON ahead |
| 2026-03-09 | 92.99 | 80.11 | +0.80 | AON ahead |
| 2026-03-06 | 95.16 | 81.49 | +0.89 | AON ahead |
| 2026-03-05 | 94.65 | 82.35 | +0.66 | AON ahead |
| 2026-03-04 | 95.32 | 82.28 | +0.78 | AON ahead |
| 2026-03-03 | 94.73 | 82.00 | +0.74 | AON ahead |
| 2026-03-02 | 94.38 | 82.98 | +0.51 | AON ahead |
| 2026-02-27 | 93.73 | 83.12 | +0.38 | near the usual relationship |
| 2026-02-26 | 92.27 | 82.48 | +0.26 | near the usual relationship |
| 2026-02-25 | 90.70 | 80.61 | +0.35 | near the usual relationship |
| 2026-02-24 | 89.22 | 79.42 | +0.33 | near the usual relationship |
| 2026-02-23 | 88.09 | 78.78 | +0.26 | near the usual relationship |
| 2026-02-20 | 90.82 | 79.82 | +0.53 | AON ahead |
| 2026-02-19 | 90.60 | 79.62 | +0.54 | AON ahead |
| 2026-02-18 | 90.24 | 79.28 | +0.55 | AON ahead |
| 2026-02-17 | 91.07 | 78.26 | +0.89 | AON ahead |
| 2026-02-13 | 89.88 | 77.48 | +0.85 | AON ahead |
| 2026-02-12 | 87.86 | 77.15 | +0.57 | AON ahead |
| 2026-02-11 | 86.60 | 77.01 | +0.38 | near the usual relationship |
| 2026-02-10 | 88.82 | 78.05 | +0.57 | AON ahead |
| 2026-02-09 | 86.70 | 76.18 | +0.57 | AON ahead |
| 2026-02-06 | 95.56 | 82.36 | +0.88 | AON ahead |
| 2026-02-05 | 95.93 | 83.46 | +0.73 | AON ahead |
| 2026-02-04 | 97.84 | 84.46 | +0.86 | AON ahead |
| 2026-02-03 | 96.90 | 83.90 | +0.82 | AON ahead |
| 2026-02-02 | 97.68 | 83.79 | +0.97 | AON ahead |
| 2026-01-30 | 97.68 | 83.77 | +0.98 | AON ahead |
| 2026-01-29 | 95.81 | 83.65 | +0.71 | AON ahead |
| 2026-01-28 | 93.03 | 79.31 | +1.09 | AON ahead |
| 2026-01-27 | 92.41 | 79.76 | +0.90 | AON ahead |
| 2026-01-26 | 94.67 | 81.75 | +0.90 | AON ahead |
| 2026-01-23 | 94.62 | 81.53 | +0.94 | AON ahead |
| 2026-01-22 | 93.86 | 80.41 | +1.04 | AON ahead |
| 2026-01-21 | 92.97 | 79.98 | +0.98 | AON ahead |
| 2026-01-20 | 94.85 | 80.57 | +1.19 | AON ahead |
| 2026-01-16 | 96.07 | 81.19 | +1.28 | AON ahead |
| 2026-01-15 | 96.34 | 81.13 | +1.35 | AON ahead |
| 2026-01-14 | 96.67 | 81.58 | +1.33 | AON ahead |
| 2026-01-13 | 96.27 | 81.32 | +1.32 | AON ahead |
| 2026-01-12 | 97.92 | 82.63 | +1.35 | AON ahead |
| 2026-01-09 | 98.01 | 82.80 | +1.34 | AON ahead |
| 2026-01-08 | 98.33 | 83.19 | +1.33 | AON ahead |
| 2026-01-07 | 97.76 | 81.41 | +1.60 | AON ahead |
| 2026-01-06 | 97.69 | 82.59 | +1.37 | AON ahead |
| 2026-01-05 | 98.14 | 83.39 | +1.30 | AON ahead |
| 2026-01-02 | 96.18 | 81.22 | +1.41 | AON ahead |
| 2025-12-31 | 98.59 | 82.58 | +1.56 | AON ahead |
| 2025-12-30 | 99.60 | 83.40 | +1.58 | AON ahead |
| 2025-12-29 | 99.66 | 83.52 | +1.58 | AON ahead |
| 2025-12-26 | 99.64 | 83.24 | +1.65 | AON ahead |
| 2025-12-24 | 99.64 | 83.50 | +1.61 | AON ahead |
| 2025-12-23 | 99.42 | 82.75 | +1.74 | AON ahead |
| 2025-12-22 | 99.31 | 82.57 | +1.78 | AON ahead |
| 2025-12-19 | 97.80 | 82.21 | +1.61 | AON ahead |
| 2025-12-18 | 98.63 | 82.67 | +1.67 | AON ahead |
| 2025-12-17 | 98.35 | 82.95 | +1.58 | AON ahead |
| 2025-12-16 | 98.29 | 83.31 | +1.51 | AON ahead |
| 2025-12-15 | 98.93 | 83.37 | +1.63 | AON ahead |
| 2025-12-12 | 98.84 | 82.89 | +1.73 | AON ahead |
| 2025-12-11 | 97.06 | 81.67 | +1.69 | AON ahead |
| 2025-12-10 | 95.00 | 80.54 | +1.58 | AON ahead |
| 2025-12-09 | 96.72 | 80.68 | +1.88 | AON ahead |
| 2025-12-08 | 95.94 | 80.83 | +1.72 | AON ahead |
| 2025-12-05 | 96.44 | 80.93 | +1.81 | AON ahead |
| 2025-12-04 | 97.14 | 81.55 | +1.83 | AON ahead |
| 2025-12-03 | 96.23 | 81.84 | +1.61 | AON ahead |
| 2025-12-02 | 96.58 | 81.62 | +1.74 | AON ahead |
| 2025-12-01 | 98.11 | 81.90 | +1.99 | AON ahead |
| 2025-11-28 | 98.88 | 81.66 | +2.21 | AON ahead |
| 2025-11-26 | 98.51 | 81.32 | +2.25 | AON ahead |
| 2025-11-25 | 98.05 | 81.02 | +2.27 | AON ahead |
| 2025-11-24 | 96.30 | 79.94 | +2.21 | AON ahead |
| 2025-11-21 | 96.81 | 80.53 | +2.20 | AON ahead |
| 2025-11-20 | 96.64 | 79.65 | +2.41 | AON ahead |
| 2025-11-19 | 96.16 | 78.84 | +2.55 | AON ahead |
| 2025-11-18 | 97.38 | 80.23 | +2.50 | AON ahead |
| 2025-11-17 | 97.79 | 80.51 | +2.56 | AON ahead |
| 2025-11-14 | 97.82 | 81.37 | +2.39 | AON ahead |
| 2025-11-13 | 98.05 | 81.83 | +2.35 | AON ahead |
| 2025-11-12 | 97.82 | 81.36 | +2.46 | AON ahead |
| 2025-11-11 | 97.76 | 80.98 | +2.59 | AON ahead |
| 2025-11-10 | 96.35 | 79.28 | +2.78 | AON ahead |
| 2025-11-07 | 96.76 | 80.14 | +2.69 | AON ahead |
| 2025-11-06 | 94.99 | 78.60 | +2.77 | AON ahead |
| 2025-11-05 | 95.47 | 79.41 | +2.70 | AON ahead |
| 2025-11-04 | 96.17 | 80.34 | +2.65 | AON ahead |
| 2025-11-03 | 94.95 | 78.84 | +2.84 | AON ahead |
| 2025-10-31 | 95.18 | 79.30 | +2.82 | AON ahead |
| 2025-10-30 | 91.69 | 79.53 | +1.91 | AON ahead |
| 2025-10-29 | 91.10 | 80.12 | +1.60 | AON ahead |
| 2025-10-28 | 92.19 | 81.38 | +1.52 | AON ahead |
| 2025-10-27 | 94.12 | 83.51 | +1.41 | AON ahead |
| 2025-10-24 | 94.36 | 83.04 | +1.62 | AON ahead |
| 2025-10-23 | 95.37 | 83.72 | +1.70 | AON ahead |
| 2025-10-22 | 95.86 | 84.27 | +1.68 | AON ahead |
| 2025-10-21 | 95.95 | 84.10 | +1.76 | AON ahead |
| 2025-10-20 | 96.14 | 84.53 | +1.70 | AON ahead |
| 2025-10-17 | 96.83 | 84.39 | +1.93 | AON ahead |
| 2025-10-16 | 95.86 | 83.01 | +2.11 | AON ahead |
| 2025-10-15 | 99.40 | 90.74 | +0.85 | AON ahead |
| 2025-10-14 | 100.72 | 92.15 | +0.80 | AON ahead |
| 2025-10-13 | 98.72 | 91.41 | +0.52 | AON ahead |
| 2025-10-10 | 100.62 | 92.15 | +0.79 | AON ahead |
| 2025-10-09 | 100.70 | 91.69 | +0.93 | AON ahead |
| 2025-10-08 | 102.08 | 91.14 | +1.41 | AON ahead |
| 2025-10-07 | 102.51 | 90.73 | +1.62 | AON ahead |
| 2025-10-06 | 102.17 | 89.62 | +1.85 | AON ahead |
| 2025-10-03 | 101.64 | 89.53 | +1.77 | AON ahead |
| 2025-10-02 | 100.78 | 88.83 | +1.76 | AON ahead |
| 2025-10-01 | 100.61 | 89.60 | +1.53 | AON ahead |
| 2025-09-30 | 99.62 | 89.70 | +1.28 | AON ahead |
| 2025-09-29 | 99.08 | 89.13 | +1.31 | AON ahead |
| 2025-09-26 | 99.48 | 88.83 | +1.50 | AON ahead |
| 2025-09-25 | 98.24 | 88.12 | +1.40 | AON ahead |
| 2025-09-24 | 98.83 | 88.87 | +1.35 | AON ahead |
| 2025-09-23 | 98.64 | 87.89 | +1.57 | AON ahead |
| 2025-09-22 | 98.75 | 87.71 | +1.66 | AON ahead |
| 2025-09-19 | 98.15 | 87.59 | +1.56 | AON ahead |
| 2025-09-18 | 98.56 | 87.31 | +1.74 | AON ahead |
| 2025-09-17 | 100.02 | 87.87 | +1.94 | AON ahead |
| 2025-09-16 | 99.62 | 87.61 | +1.93 | AON ahead |
| 2025-09-15 | 101.64 | 88.18 | +2.26 | AON ahead |
| 2025-09-12 | 103.92 | 90.33 | +2.23 | AON ahead |
| 2025-09-11 | 104.00 | 90.56 | +2.21 | AON ahead |
| 2025-09-10 | 101.24 | 88.48 | +2.15 | AON ahead |
| 2025-09-09 | 102.36 | 89.86 | +2.06 | AON ahead |
| 2025-09-08 | 103.37 | 90.56 | +2.12 | AON ahead |
| 2025-09-05 | 103.52 | 90.69 | +2.14 | AON ahead |
| 2025-09-04 | 104.35 | 91.74 | +2.08 | AON ahead |
| 2025-09-03 | 104.49 | 91.37 | +2.22 | AON ahead |
| 2025-09-02 | 103.92 | 91.44 | +2.09 | AON ahead |
| 2025-08-29 | 102.53 | 91.61 | +1.75 | AON ahead |
| 2025-08-28 | 102.41 | 91.89 | +1.66 | AON ahead |
| 2025-08-27 | 102.92 | 91.86 | +1.79 | AON ahead |
| 2025-08-26 | 103.09 | 91.88 | +1.84 | AON ahead |
| 2025-08-25 | 103.63 | 92.14 | +1.91 | AON ahead |
| 2025-08-22 | 104.80 | 93.72 | +1.79 | AON ahead |
| 2025-08-21 | 104.84 | 93.97 | +1.75 | AON ahead |
| 2025-08-20 | 104.49 | 94.01 | +1.67 | AON ahead |
| 2025-08-19 | 104.17 | 93.89 | +1.64 | AON ahead |
| 2025-08-18 | 102.08 | 92.43 | +1.55 | AON ahead |
| 2025-08-15 | 102.54 | 92.23 | +1.70 | AON ahead |
| 2025-08-14 | 102.35 | 92.13 | +1.70 | AON ahead |
| 2025-08-13 | 103.63 | 93.19 | +1.74 | AON ahead |
| 2025-08-12 | 101.64 | 90.99 | +1.85 | AON ahead |
| 2025-08-11 | 102.84 | 90.51 | +2.24 | AON ahead |
| 2025-08-08 | 102.37 | 90.66 | +2.12 | AON ahead |
| 2025-08-07 | 101.98 | 90.50 | +2.10 | AON ahead |
| 2025-08-06 | 101.61 | 90.76 | +1.96 | AON ahead |
| 2025-08-05 | 101.03 | 89.25 | +2.22 | AON ahead |
| 2025-08-04 | 100.69 | 88.61 | +2.33 | AON ahead |
| 2025-08-01 | 98.75 | 88.04 | +2.06 | AON ahead |
| 2025-07-31 | 99.38 | 88.67 | +2.05 | AON ahead |
| 2025-07-30 | 99.28 | 89.27 | +1.89 | AON ahead |
| 2025-07-29 | 98.91 | 90.32 | +1.54 | AON ahead |
| 2025-07-28 | 103.14 | 91.81 | +2.07 | AON ahead |
| 2025-07-25 | 104.18 | 93.65 | +1.85 | AON ahead |
| 2025-07-24 | 99.63 | 92.73 | +1.12 | AON ahead |
| 2025-07-23 | 99.82 | 93.39 | +1.01 | AON ahead |
| 2025-07-22 | 98.96 | 93.61 | +0.79 | AON ahead |
| 2025-07-21 | 98.04 | 93.48 | +0.64 | AON ahead |
| 2025-07-18 | 99.49 | 94.49 | +0.72 | AON ahead |
| 2025-07-17 | 99.08 | 93.94 | +0.75 | AON ahead |
| 2025-07-16 | 99.06 | 94.36 | +0.67 | AON ahead |
| 2025-07-15 | 98.45 | 93.88 | +0.65 | AON ahead |
| 2025-07-14 | 100.53 | 95.06 | +0.80 | AON ahead |
| 2025-07-11 | 99.37 | 94.25 | +0.75 | AON ahead |
| 2025-07-10 | 100.30 | 95.57 | +0.68 | AON ahead |
| 2025-07-09 | 99.72 | 95.33 | +0.63 | AON ahead |
| 2025-07-08 | 99.06 | 94.89 | +0.60 | AON ahead |
| 2025-07-07 | 98.69 | 94.88 | +0.54 | AON ahead |
| 2025-07-03 | 99.11 | 95.74 | +0.47 | near the usual relationship |
| 2025-07-02 | 98.22 | 94.69 | +0.51 | AON ahead |
| 2025-07-01 | 99.72 | 96.96 | +0.38 | near the usual relationship |
| 2025-06-30 | 99.67 | 97.32 | +0.32 | near the usual relationship |
| 2025-06-27 | 98.55 | 96.58 | +0.27 | near the usual relationship |
| 2025-06-26 | 98.78 | 96.15 | +0.38 | near the usual relationship |
| 2025-06-25 | 99.03 | 96.28 | +0.41 | near the usual relationship |
| 2025-06-24 | 100.77 | 97.78 | +0.44 | near the usual relationship |
| 2025-06-23 | 100.56 | 97.53 | +0.46 | near the usual relationship |
| 2025-06-20 | 99.10 | 96.24 | +0.44 | near the usual relationship |
| 2025-06-18 | 98.02 | 95.40 | +0.42 | near the usual relationship |
| 2025-06-17 | 98.01 | 96.16 | +0.30 | near the usual relationship |
| 2025-06-16 | 97.80 | 96.43 | +0.24 | near the usual relationship |
| 2025-06-13 | 98.62 | 96.76 | +0.31 | near the usual relationship |
| 2025-06-12 | 99.40 | 97.66 | +0.30 | near the usual relationship |
| 2025-06-11 | 97.64 | 96.72 | +0.19 | near the usual relationship |
| 2025-06-10 | 98.26 | 97.09 | +0.23 | near the usual relationship |
| 2025-06-09 | 98.85 | 99.05 | +0.04 | near the usual relationship |
| 2025-06-06 | 103.68 | 102.38 | +0.26 | near the usual relationship |
| 2025-06-05 | 103.51 | 101.87 | +0.31 | near the usual relationship |
| 2025-06-04 | 104.10 | 103.41 | +0.19 | near the usual relationship |
| 2025-06-03 | 104.62 | 104.54 | +0.12 | near the usual relationship |
| 2025-06-02 | 105.09 | 104.50 | +0.19 | near the usual relationship |
| 2025-05-30 | 103.95 | 104.01 | +0.11 | near the usual relationship |
| 2025-05-29 | 102.51 | 103.04 | +0.06 | near the usual relationship |
| 2025-05-28 | 100.95 | 102.16 | -0.02 | near the usual relationship |
| 2025-05-27 | 101.99 | 103.06 | +0.00 | near the usual relationship |
| 2025-05-23 | 99.61 | 102.08 | -0.17 | near the usual relationship |
| 2025-05-22 | 99.27 | 101.70 | -0.16 | near the usual relationship |
| 2025-05-21 | 100.04 | 101.94 | -0.09 | near the usual relationship |
| 2025-05-20 | 101.26 | 102.74 | -0.02 | near the usual relationship |
| 2025-05-19 | 101.96 | 103.20 | +0.01 | near the usual relationship |
| 2025-05-16 | 101.11 | 103.00 | -0.06 | near the usual relationship |
| 2025-05-15 | 100.18 | 101.15 | +0.06 | near the usual relationship |
| 2025-05-14 | 98.40 | 99.04 | +0.10 | near the usual relationship |
| 2025-05-13 | 99.20 | 99.60 | +0.14 | near the usual relationship |
| 2025-05-12 | 98.78 | 101.05 | -0.09 | near the usual relationship |
| 2025-05-09 | 98.99 | 100.97 | -0.05 | near the usual relationship |
| 2025-05-08 | 99.77 | 101.68 | -0.04 | near the usual relationship |
| 2025-05-07 | 100.50 | 101.45 | +0.09 | near the usual relationship |
| 2025-05-06 | 100.00 | 100.91 | +0.10 | near the usual relationship |
| 2025-05-05 | 99.32 | 100.85 | +0.03 | near the usual relationship |
| 2025-05-02 | 99.53 | 101.17 | +0.02 | near the usual relationship |
| 2025-05-01 | 98.21 | 99.71 | +0.04 | near the usual relationship |
| 2025-04-30 | 99.12 | 100.36 | +0.08 | near the usual relationship |
| 2025-04-29 | 97.76 | 98.82 | +0.10 | near the usual relationship |
| 2025-04-28 | 95.96 | 98.13 | -0.04 | near the usual relationship |
| 2025-04-25 | 93.83 | 97.59 | -0.25 | near the usual relationship |
| 2025-04-24 | 101.99 | 97.46 | +0.79 | AON ahead |
| 2025-04-23 | 103.05 | 97.50 | +0.92 | AON ahead |
| 2025-04-22 | 102.96 | 97.73 | +0.88 | AON ahead |
| 2025-04-21 | 99.45 | 94.41 | +0.89 | AON ahead |
| 2025-04-17 | 102.65 | 97.96 | +0.83 | AON ahead |
| 2025-04-16 | 104.16 | 102.96 | +0.40 | near the usual relationship |
| 2025-04-15 | 105.92 | 103.43 | +0.55 | AON ahead |
| 2025-04-14 | 107.38 | 105.64 | +0.46 | near the usual relationship |
| 2025-04-11 | 105.13 | 103.86 | +0.41 | near the usual relationship |
| 2025-04-10 | 103.10 | 101.83 | +0.41 | near the usual relationship |
| 2025-04-09 | 104.31 | 102.18 | +0.52 | AON ahead |
| 2025-04-08 | 100.64 | 98.22 | +0.57 | AON ahead |
| 2025-04-07 | 101.79 | 99.59 | +0.54 | AON ahead |
| 2025-04-04 | 104.98 | 102.47 | +0.57 | AON ahead |
| 2025-04-03 | 110.16 | 108.73 | +0.43 | near the usual relationship |
| 2025-04-02 | 110.64 | 108.45 | +0.52 | AON ahead |
| 2025-04-01 | 111.42 | 108.61 | +0.58 | AON ahead |
| 2025-03-31 | 111.50 | 108.62 | +0.59 | AON ahead |
| 2025-03-28 | 110.23 | 107.89 | +0.53 | AON ahead |
| 2025-03-27 | 111.63 | 108.35 | +0.64 | AON ahead |
| 2025-03-26 | 110.84 | 106.29 | +0.79 | AON ahead |
| 2025-03-25 | 110.68 | 105.32 | +0.89 | AON ahead |
| 2025-03-24 | 109.84 | 104.43 | +0.91 | AON ahead |
| 2025-03-21 | 109.06 | 103.41 | +0.95 | AON ahead |
| 2025-03-20 | 109.85 | 103.88 | +0.98 | AON ahead |
| 2025-03-19 | 109.07 | 103.52 | +0.94 | AON ahead |
| 2025-03-18 | 108.97 | 103.34 | +0.96 | AON ahead |
| 2025-03-17 | 109.23 | 103.67 | +0.96 | AON ahead |
| 2025-03-14 | 111.42 | 103.06 | +1.29 | AON ahead |
| 2025-03-13 | 110.13 | 102.35 | +1.24 | AON ahead |
| 2025-03-12 | 111.28 | 102.29 | +1.39 | AON ahead |
| 2025-03-11 | 111.68 | 103.76 | +1.26 | AON ahead |
| 2025-03-10 | 111.47 | 105.15 | +1.08 | AON ahead |
| 2025-03-07 | 112.62 | 104.82 | +1.25 | AON ahead |
| 2025-03-06 | 112.20 | 105.23 | +1.16 | AON ahead |
| 2025-03-05 | 112.89 | 105.85 | +1.18 | AON ahead |
| 2025-03-04 | 113.06 | 105.39 | +1.26 | AON ahead |
| 2025-03-03 | 114.36 | 106.60 | +1.27 | AON ahead |
| 2025-02-28 | 114.30 | 105.87 | +1.36 | AON ahead |
| 2025-02-27 | 112.87 | 104.43 | +1.39 | AON ahead |
| 2025-02-26 | 111.54 | 103.07 | +1.41 | AON ahead |
| 2025-02-25 | 111.07 | 104.25 | +1.22 | AON ahead |
| 2025-02-24 | 109.57 | 103.65 | +1.12 | AON ahead |
| 2025-02-21 | 108.84 | 102.38 | +1.20 | AON ahead |
| 2025-02-20 | 109.82 | 102.63 | +1.30 | AON ahead |
| 2025-02-19 | 110.32 | 102.88 | +1.34 | AON ahead |
| 2025-02-18 | 109.26 | 102.44 | +1.27 | AON ahead |
| 2025-02-14 | 108.12 | 101.86 | +1.22 | AON ahead |
| 2025-02-13 | 109.04 | 102.87 | +1.20 | AON ahead |
| 2025-02-12 | 108.05 | 101.92 | +1.21 | AON ahead |
| 2025-02-11 | 107.34 | 101.49 | +1.19 | AON ahead |
| 2025-02-10 | 107.73 | 101.51 | +1.24 | AON ahead |
| 2025-02-07 | 107.98 | 101.22 | +1.32 | AON ahead |
| 2025-02-06 | 107.48 | 100.60 | +1.35 | AON ahead |
| 2025-02-05 | 106.83 | 100.38 | +1.31 | AON ahead |
| 2025-02-04 | 105.46 | 99.29 | +1.29 | AON ahead |
| 2025-02-03 | 104.74 | 97.61 | +1.44 | AON ahead |
| 2025-01-31 | 103.60 | 96.54 | +1.46 | AON ahead |
| 2025-01-30 | 103.97 | 98.30 | +1.27 | AON ahead |
| 2025-01-29 | 102.46 | 97.62 | +1.17 | AON ahead |
| 2025-01-28 | 103.79 | 98.32 | +1.25 | AON ahead |
| 2025-01-27 | 105.27 | 99.64 | +1.27 | AON ahead |
| 2025-01-24 | 103.14 | 97.46 | +1.31 | AON ahead |
| 2025-01-23 | 101.88 | 96.78 | +1.24 | AON ahead |
| 2025-01-22 | 102.62 | 96.74 | +1.36 | AON ahead |
| 2025-01-21 | 102.84 | 97.13 | +1.34 | AON ahead |
| 2025-01-17 | 102.30 | 95.80 | +1.47 | AON ahead |
| 2025-01-16 | 102.84 | 96.27 | +1.49 | AON ahead |
| 2025-01-15 | 100.91 | 94.63 | +1.48 | AON ahead |
| 2025-01-14 | 101.32 | 94.97 | +1.49 | AON ahead |
| 2025-01-13 | 99.09 | 94.14 | +1.31 | AON ahead |
| 2025-01-10 | 97.65 | 93.08 | +1.27 | AON ahead |
| 2025-01-08 | 98.47 | 94.08 | +1.25 | AON ahead |
| 2025-01-07 | 97.35 | 93.47 | +1.18 | AON ahead |
| 2025-01-06 | 97.36 | 92.80 | +1.30 | AON ahead |
| 2025-01-03 | 98.90 | 94.04 | +1.34 | AON ahead |
| 2025-01-02 | 99.18 | 94.07 | +1.39 | AON ahead |
| 2024-12-31 | 100.34 | 94.55 | +1.50 | AON ahead |
| 2024-12-30 | 100.01 | 94.36 | +1.50 | AON ahead |
| 2024-12-27 | 100.68 | 95.02 | +1.50 | AON ahead |
| 2024-12-26 | 100.99 | 95.34 | +1.51 | AON ahead |
| 2024-12-24 | 101.03 | 95.27 | +1.54 | AON ahead |
| 2024-12-23 | 100.10 | 94.44 | +1.54 | AON ahead |
| 2024-12-20 | 100.15 | 94.25 | +1.59 | AON ahead |
| 2024-12-19 | 98.83 | 93.63 | +1.49 | AON ahead |
| 2024-12-18 | 98.51 | 93.43 | +1.48 | AON ahead |
| 2024-12-17 | 100.27 | 94.89 | +1.51 | AON ahead |
| 2024-12-16 | 101.07 | 94.86 | +1.64 | AON ahead |
| 2024-12-13 | 100.91 | 95.73 | +1.48 | AON ahead |
| 2024-12-12 | 101.34 | 96.11 | +1.49 | AON ahead |
| 2024-12-11 | 101.31 | 95.41 | +1.60 | AON ahead |
| 2024-12-10 | 100.94 | 95.96 | +1.46 | AON ahead |
| 2024-12-09 | 102.79 | 97.11 | +1.56 | AON ahead |
| 2024-12-06 | 105.61 | 100.22 | +1.50 | AON ahead |
| 2024-12-05 | 106.09 | 101.60 | +1.36 | AON ahead |
| 2024-12-04 | 106.72 | 102.26 | +1.35 | AON ahead |
| 2024-12-03 | 107.72 | 102.45 | +1.47 | AON ahead |
| 2024-12-02 | 108.32 | 103.73 | +1.36 | AON ahead |
| 2024-11-29 | 109.39 | 103.81 | +1.51 | AON ahead |
| 2024-11-27 | 109.88 | 103.82 | +1.58 | AON ahead |
| 2024-11-26 | 109.03 | 103.61 | +1.50 | AON ahead |
| 2024-11-25 | 108.88 | 102.69 | +1.62 | AON ahead |
| 2024-11-22 | 107.90 | 101.41 | +1.68 | AON ahead |
| 2024-11-21 | 106.90 | 99.89 | +1.78 | AON ahead |
| 2024-11-20 | 106.19 | 98.80 | +1.86 | AON ahead |
| 2024-11-19 | 105.93 | 98.25 | +1.91 | AON ahead |
| 2024-11-18 | 106.31 | 99.56 | +1.76 | AON ahead |
| 2024-11-15 | 105.97 | 98.88 | +1.82 | AON ahead |
| 2024-11-14 | 105.14 | 98.59 | +1.75 | AON ahead |
| 2024-11-13 | 108.10 | 100.48 | +1.90 | AON ahead |
| 2024-11-12 | 107.19 | 100.23 | +1.81 | AON ahead |
| 2024-11-11 | 107.11 | 99.61 | +1.90 | AON ahead |
| 2024-11-08 | 107.22 | 100.31 | +1.81 | AON ahead |
| 2024-11-07 | 106.13 | 99.34 | +1.80 | AON ahead |
| 2024-11-06 | 106.52 | 99.37 | +1.86 | AON ahead |
| 2024-11-05 | 103.01 | 98.62 | +1.45 | AON ahead |
| 2024-11-04 | 102.15 | 98.44 | +1.34 | AON ahead |
| 2024-11-01 | 101.81 | 97.53 | +1.44 | AON ahead |
| 2024-10-31 | 102.50 | 97.14 | +1.62 | AON ahead |
| 2024-10-30 | 103.22 | 98.38 | +1.53 | AON ahead |
| 2024-10-29 | 103.64 | 98.68 | +1.55 | AON ahead |
| 2024-10-28 | 103.85 | 98.74 | +1.57 | AON ahead |
| 2024-10-25 | 104.89 | 98.51 | +1.77 | AON ahead |
| 2024-10-24 | 99.70 | 99.03 | +0.85 | AON ahead |
| 2024-10-23 | 100.10 | 99.48 | +0.84 | AON ahead |
| 2024-10-22 | 99.50 | 98.74 | +0.86 | AON ahead |
| 2024-10-21 | 99.86 | 98.84 | +0.89 | AON ahead |
| 2024-10-18 | 100.00 | 100.00 | +0.72 | AON ahead |
One-day company-specific moves (4+ standard deviations, which block ideas for 10 sessions): Oct 25, 2024 (AON +5.2%, MRSH -0.5%); Apr 25, 2025 (AON -8.0%, MRSH +0.1%); Oct 16, 2025 (AON -3.6%, MRSH -8.5%); Jul 29, 2026 (AON -1.1%, MRSH +2.8%); Aug 31, 2026 (AON -9.5%, MRSH -1.5%). Upcoming earnings: AON Oct 28, 2026 (pre-market).
Paired trades
The shared paper book and the replay, kept apart
Forward paper record
No paper position on this pair yet.
Historical simulation (a diagnostic, same rules)
3 simulated trades to Oct 20, 2026: -2.23% per trade on average after costs, 1 won.
| Legs | Entered | Exited | Why | Days | Before costs | Costs + borrow | After costs |
|---|---|---|---|---|---|---|---|
| Long MRSH · Short AON | Jul 29, 2025 | May 15, 2026 | divergence stop | 290 | -$705.24 | -$71.08 | -$727.79 (-7.28%) |
| Long AON · Short MRSH | Apr 30, 2020 | Jun 12, 2020 | divergence stop | 43 | -$343.00 | -$52.16 | -$400.63 (-4.01%) |
| Long MRSH · Short AON | Apr 8, 2020 | Apr 16, 2020 | converged | 8 | $505.12 | -$46.14 | $459.99 (+4.60%) |
Per $10,000 a leg. A replay on today's companies cannot prove an edge.
The companies
AON and MRSH at a glance
AON Aon plc Class A Ordinary Shares (Ireland)
- Listing
- NYSE · SEC CIK 315293
- Industry
- Specialty Insurers · SIC 6411 Insurance Agents, Brokers & Service
- Market value
- $61.5B
- Price history
- 2,521 daily closes, Oct 12, 2016 to Oct 22, 2026
MRSH Marsh
- Listing
- NYSE · SEC CIK 62709
- Industry
- Specialty Insurers · SIC 6411 Insurance Agents, Brokers & Service
- Market value
- $89.6B
- Price history
- 2,521 daily closes, Oct 12, 2016 to Oct 22, 2026
Daily prices: Nasdaq.com. Filings and industry codes: SEC EDGAR. Earnings dates: Nasdaq earnings calendar.
Related
All pairs →Other rivals of AON and MRSH
| Pair | Status | Ahead now | Industry |
|---|---|---|---|
| AJG / AON | Watchlist | AJG by 2.55 sd | Specialty Insurers |
| MRSH / AJG | Watchlist | AJG by 0.46 sd | Specialty Insurers |
Follow the research behind the paper book
Boostio is a research-first platform in private beta: crypto candidates, daily market stories, public paper trading and now rival stocks. Exploring these pages stays free and open.
Explore the private betaPaper only: hypothetical paired positions with modelled costs. No broker, no orders, no real money. A historical simulation is a diagnostic, not proof of an edge. Not investment advice.
