Aon plc options tape
Read from CBOE's delayed chain on 23 September 2026, with Aon plc at $286.10: open interest within 90 days was 2,767 call and 3,325 put contracts, a put/call ratio of 1.2; the day's volume was 495 calls and 1,236 puts (2.5). The most call open interest sits at the $360.00 strike (553 contracts) and the most put open interest at $310.00 (1,088). The at-the-money straddle for 16 October 2026, 23 days out, was priced at 5.7% of spot. For 16 October 2026, implied volatility was 29.5% at the put 5% below spot and 27.3% at the call 5% above, +2.3 points.
Where the open interest sits
| Side | Strike | Open interest |
|---|---|---|
| Calls | $360.00 | 553 |
| Puts | $310.00 | 1,088 |
The strike with the most open interest on each side, across expiries within 90 days.
Strikes where the day's volume was at least twice the open interest
| Contract | Volume | Open interest before | Premium traded |
|---|---|---|---|
| 18 December 2026 put at $260.00 | 503 | 8 | $324,435 |
| 16 October 2026 put at $280.00 | 382 | 94 | $194,820 |
Volume of at least 200 contracts and at least twice the open interest, with at least $25,000 of premium at the mid; contracts expiring the same day are left out. Premium is mid price times volume times 100.
Source
CBOE delayed quotes for AON, the free 15-minute-delayed chain, read once a day. Figures describe positioning; they are not a forecast.
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