Aon (AON) insider buying and selling
Every Table I transaction reported by directors and officers of S&P 500 companies on SEC Form 4 filings (2 business days to file): each row labeled with its official transaction code, nothing filtered out beforehand.
Open-market purchases (code P) are the rare signal, in green; sales (code S) are common and often pre-scheduled (10b5-1). Table II (derivatives) is not included: its prices are exercise prices, not market values. Guide: insider buying.
| Date | Ticker | Insider | Role | Shares | Price | Amount | % of stake | Type / filing |
|---|
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Aon plc (AON) insider buying and selling: 2 purchases, 6 sales
82 Form 4 Table I transactions filed with the SEC by Aon plc insiders between 2025-09-30 and 2026-09-03 (15-month history): 2 open-market purchases and 6 sales, plus 74 transactions under other Form 4 codes, broken down one by one below. The largest open-market trade is a purchase of $6.5M by Knight Lester B on 2026-09-02.
Aon insider buying and selling over the last 12 months
Between Oct 21, 2025 and Oct 20, 2026, Aon insiders filed 2 purchases worth $7.8M and 6 sales worth $7.8M on the open market. The net balance is on the buy side: $76k more bought than sold.
The biggest buyer was Knight Lester B (Director): $7.8M in 2 purchases, the only buyer. The biggest seller was Zeidel Darren (General Counsel): $7.8M in 6 sales, the only seller.
The largest trade of the period was a purchase of $6.5M on Sep 2, 2026, by Knight Lester B (Director). Form 4 on sec.gov (0001193125-26-382419).
Of the 6 sales, 4 (67%, $3.3M) carry the 10b5-1 plan flag on the Form 4, meaning they were scheduled months ahead; the other 2 do not.
The last three months show 1 purchase and 1 sale, against 0 and 2 in the three before. The latest purchase is from Sep 2, 2026; the latest sale from Jul 28, 2026.
Against its sector (Financial Services, 70 companies with an insider page on this site), over the same dates the median is 10 sales and 0 purchases on the open market. Aon has more sales than 21 of the other 69, ranks 10 of 70 by net dollars bought, and 32 of the 70 have at least one purchase, Aon included.
The 20 most important trades
The 2 open-market purchases first, then the rest, each type from largest to smallest. The full history is in the tool above, already searched.
See all 82 AON trades in the full history →
| Trade date | Filed | Insider | Role | Amount | Code | Filing |
|---|---|---|---|---|---|---|
| 2026-09-02 | 2026-09-03 | Knight Lester B | Director | $6.5M | P — Open-market purchase Indirect holding, through: By Family Partnership 6 Form 4 footnotesF1 The price reported is a weighted average price. Shares were purchased in a series of transactions within the same trading day at prices ranging from $325.03 to $326.02, inclusive. Full information regarding the number of shares purchased at each separate price is available upon request by the Commission staff, the issuer, or a security holder of the issuer. F2 The price reported is a weighted average price. Shares were purchased in a series of transactions within the same trading day at prices ranging from $326.03 to $327.02, inclusive. Full information regarding the number of shares purchased at each separate price is available upon request by the Commission staff, the issuer, or a security holder of the issuer. F3 The price reported is a weighted average price. Shares were purchased in a series of transactions within the same trading day at prices ranging from $327.04 to $328.03, inclusive. Full information regarding the number of shares purchased at each separate price is available upon request by the Commission staff, the issuer, or a security holder of the issuer. F4 The price reported is a weighted average price. Shares were purchased in a series of transactions within the same trading day at prices ranging from $328.04 to $329.03, inclusive. Full information regarding the number of shares purchased at each separate price is available upon request by the Commission staff, the issuer, or a security holder of the issuer. F5 The price reported is a weighted average price. Shares were purchased in a series of transactions within the same trading day at prices ranging from $329.08 to $330.07, inclusive. Full information regarding the number of shares purchased at each separate price is available upon request by the Commission staff, the issuer, or a security holder of the issuer. F6 The price reported is a weighted average price. Shares were purchased in a series of transactions within the same trading day at prices ranging from $330.09 to $330.88, inclusive. Full information regarding the number of shares purchased at each separate price is available upon request by the Commission staff, the issuer, or a security holder of the issuer. | SEC |
| 2026-02-10 | 2026-02-12 | Knight Lester B | Director | $1.3M | P — Open-market purchase Indirect holding, through: By Family Partnership Form 4 footnoteF1 The price reported is a weighted average price. Shares were purchased in a series of transactions within the same trading day at prices ranging from $319.00 to $319.47, inclusive. Full information regarding the number of shares purchased at each separate price is available upon request by the Commission staff, the issuer, or a security holder of the issuer | SEC |
| 2025-11-05 | 2025-11-07 | Zeidel Darren | General Counsel | $3.0M | S — Open-market sale2 Form 4 footnotesF1 The price reported is a weighted average price. Shares were sold in a series of transactions within the same trading day at prices ranging from $344.00 to $344.99, inclusive. Full information regarding the number of shares sold at each separate price is available upon request by the Commission staff, the issuer, or a security holder of the issuer. F2 The price reported is a weighted average price. Shares were sold in a series of transactions within the same trading day at prices ranging from $345.00 to $344.51, inclusive. Full information regarding the number of shares sold at each separate price is available upon request by the Commission staff, the issuer, or a security holder of the issuer. | SEC |
| 2026-02-17 | 2026-02-19 | Zeidel Darren | General Counsel | $1.6M | S — Open-market sale (scheduled 10b5-1)Form 4 footnoteF1 The transaction reported was effected pursuant to a trading plan meeting the requirements of SEC Rule 10b5-1 entered into on November 5, 2025. | SEC |
| 2026-02-26 | 2026-03-02 | Zeidel Darren | General Counsel | $1.4M | S — Open-market saleForm 4 footnoteF1 The price reported is a weighted average price. Shares were sold in a series of transactions within the same trading day at prices ranging from $329.68 to $330.015, inclusive. Full information regarding the number of shares sold at each separate price is available upon request by the Commission staff, the issuer, or a security holder of the issuer. | SEC |
| 2026-07-17 | 2026-07-21 | Zeidel Darren | General Counsel | $726k | S — Open-market sale (scheduled 10b5-1)Form 4 footnoteF1 The transaction reported was effected pursuant to a trading plan meeting the requirements of SEC Rule 10b5-1 entered into on November 5, 2025. | SEC |
| 2026-07-28 | 2026-07-30 | Zeidel Darren | General Counsel | $718k | S — Open-market sale (scheduled 10b5-1)Form 4 footnoteF1 The transaction reported was effected pursuant to a trading plan meeting the requirements of SEC Rule 10b5-1 entered into on November 5, 2025. | SEC |
| 2026-07-07 | 2026-07-09 | Zeidel Darren | General Counsel | $216k | S — Open-market sale (scheduled 10b5-1)Form 4 footnoteF1 The transaction reported was effected pursuant to a trading plan meeting the requirements of SEC Rule 10b5-1 entered into on November 5, 2025. | SEC |
| 2026-02-12 | 2026-02-17 | Case Gregory C | President & CEO | $10.8M | F — Tax withholding (shares surrendered for taxes)3 Form 4 footnotesF2 Class A Ordinary Shares withheld by the issuer for payment of taxes in connection with the vesting of the award. F3 On May 5, 2025, the GRAT returned 161,104 shares to the reporting person as an annuity payment; and on February 9, 2026 the GRAT returned 201,484 shares to the reporting person as an annuity payment. F4 On November 7, 2025, the GRAT returned 63,500 shares to the reporting person as an annuity payment. | SEC |
| 2026-02-12 | 2026-02-17 | Stevens Lisa | Chief Administrative Officer | $2.4M | F — Tax withholding (shares surrendered for taxes)Form 4 footnoteF3 Class A Ordinary Shares withheld by the issuer for payment of taxes in connection with the vesting of the award. | SEC |
| 2026-02-12 | 2026-02-17 | Marcell Andy | Global CEO, Solution Lines | $2.1M | F — Tax withholding (shares surrendered for taxes)Form 4 footnoteF2 Class A Ordinary Shares withheld by the issuer for payment of taxes in connection with the vesting of the award. | SEC |
| 2026-02-12 | 2026-02-17 | Goltermann Lori | CEO, Regions & North America | $853k | F — Tax withholding (shares surrendered for taxes)Form 4 footnoteF3 Class A Ordinary Shares withheld by the issuer for payment of taxes in connection with the vesting of the award. | SEC |
| 2026-02-12 | 2026-02-17 | Zeidel Darren | General Counsel | $848k | F — Tax withholding (shares surrendered for taxes)Form 4 footnoteF2 Class A Ordinary Shares withheld by the issuer for payment of taxes in connection with the vesting of the award. | SEC |
| 2026-07-01 | 2026-07-06 | Reese Edmund | Chief Financial Officer | $755k | F — Tax withholding (shares surrendered for taxes)Form 4 footnoteF2 Class A Ordinary Shares withheld by the issuer for payment of taxes in connection with the vesting of the award. | SEC |
| 2026-02-12 | 2026-02-17 | Simon Mindy F. | Chief Operating Officer | $748k | F — Tax withholding (shares surrendered for taxes)Form 4 footnoteF2 Class A Ordinary Shares withheld by the issuer for payment of taxes in connection with the vesting of the award. | SEC |
| 2026-02-12 | 2026-02-17 | Corona Anne | Chief Commercial Officer | $442k | F — Tax withholding (shares surrendered for taxes)Form 4 footnoteF2 Class A Ordinary Shares withheld by the issuer for payment of taxes in connection with the vesting of the award. | SEC |
| 2026-02-17 | 2026-02-19 | Case Gregory C | President & CEO | $327k | F — Tax withholding (shares surrendered for taxes)Form 4 footnoteF2 Class A Ordinary Shares withheld by the issuer for payment of withholding taxes in connection with the vesting of the award. | SEC |
| 2026-02-13 | 2026-02-17 | Stevens Lisa | Chief Administrative Officer | $300k | F — Tax withholding (shares surrendered for taxes)Form 4 footnoteF3 Class A Ordinary Shares withheld by the issuer for payment of taxes in connection with the vesting of the award. | SEC |
| 2026-03-13 | 2026-03-17 | Marcell Andy | Global CEO, Solution Lines | $255k | F — Tax withholding (shares surrendered for taxes)Form 4 footnoteF2 Class A Ordinary Shares withheld by the issuer for payment of taxes in connection with the vesting of the award. | SEC |
| 2025-11-14 | 2025-11-18 | Simon Mindy F. | Chief Operating Officer | $212k | F — Tax withholding (shares surrendered for taxes)Form 4 footnoteF2 Class A Ordinary Shares withheld by the issuer for payment of taxes in connection with the vesting of the award. | SEC |
The period balance: money in, money out
Across the Form 4 filings submitted between Sep 30, 2025 and Sep 3, 2026, Aon plc open-market activity adds up to 2 purchases worth $7.8M and 6 sales worth $7.8M. The net balance is $76k on the buy side.
Only codes P and S count, where an insider puts in or takes out their own money. A buying balance like Aon plc's is the less common case in the S&P 500: its insiders are already paid in stock and still put in their own money. It is not a recommendation to buy or sell: it is what was filed.
Every transaction, code by code
| Code | What it means | Trades | Reported amount |
|---|---|---|---|
| F | Tax withholding (shares surrendered for taxes) | 32 | $21.3M |
| A | Grant or award | 20 | $0 |
| M | Option exercise | 13 | $0 |
| G | Gift | 9 | $0 |
| S | Open-market sale | 6 | $7.8M |
| P | Open-market purchase | 2 | $7.8M |
| Total | Everything filed in the period | 82 | $36.9M |
42 of the 82 rows carry no usable amount on the Form 4: they count as trades and add $0. The code labels come from the SEC index.
Who has traded
Over the 15 months of history, 20 distinct people or entities have filed Aon plc transactions: 1 bought on the open market and 1 sold. Counted by CIK, the fixed number the SEC gives each filer, and not by name, which each filer types their own way.
| Filer | Role | Transactions | Bought (count) | Sold (count) | Last filed |
|---|---|---|---|---|---|
| Knight Lester B | Director | 4 | $7.8M (2) | — | 2026-09-03 |
| Zeidel Darren | General Counsel | 10 | — | $7.8M (6) | 2026-07-30 |
| Case Gregory C | President & CEO | 8 | — | — | 2026-02-20 |
| Corona Anne | Chief Commercial Officer | 6 | — | — | 2026-03-17 |
| Goltermann Lori | CEO, Regions & North America | 6 | — | — | 2026-03-17 |
| Marcell Andy | Global CEO, Solution Lines | 6 | — | — | 2026-03-17 |
| Simon Mindy F. | Chief Operating Officer | 6 | — | — | 2026-02-17 |
| Stevens Lisa | Chief Administrative Officer | 5 | — | — | 2026-02-19 |
Shown here are the 8 who moved the most money, out of 20. The rest are in the full history, one link above. The name links to all their trades, in any company. "Transactions" counts any code; the money, open market only. Role: from their latest filing.
Month by month
By the month the trade was executed, not the month it was filed; months with no trades show zero. The busiest month was Feb 2026: 1 purchase and 2 sales, worth $4.3M. 11 of the 15 months have none.
| Month | Purchases | Amount | Sales | Amount |
|---|---|---|---|---|
| Aug 2025 | 0 | $0 | 0 | $0 |
| Sep 2025 | 0 | $0 | 0 | $0 |
| Oct 2025 | 0 | $0 | 0 | $0 |
| Nov 2025 | 0 | $0 | 1 | $3.0M |
| Dec 2025 | 0 | $0 | 0 | $0 |
| Jan 2026 | 0 | $0 | 0 | $0 |
| Feb 2026 | 1 | $1.3M | 2 | $3.1M |
| Mar 2026 | 0 | $0 | 0 | $0 |
| Apr 2026 | 0 | $0 | 0 | $0 |
| May 2026 | 0 | $0 | 0 | $0 |
| Jun 2026 | 0 | $0 | 0 | $0 |
| Jul 2026 | 0 | $0 | 3 | $1.7M |
| Aug 2026 | 0 | $0 | 0 | $0 |
| Sep 2026 | 1 | $6.5M | 0 | $0 |
| Oct 2026 | 0 | $0 | 0 | $0 |
The last month may be partial: a Form 4 is filed up to two business days later. The table does not say whether the pattern is good or bad; it says when it happened.
Other Financial Services companies with insider trades
All 500 are listed in the section index →
Which insiders are buying their own company stock →
How to read this data
4 of the 6 sales in the table are flagged as scheduled (10b5-1 plan): signed months ahead and executed automatically, so they say nothing about what the insider thinks today. Aon's 2 open-market purchases (code P) are the rare signal: insiders are already paid in stock, so buying more means putting in their own money. The latest filing is from Sep 3, 2026, and a Form 4 arrives up to two business days after the trade.
20 of the 20 rows in the table carry footnotes from the Form 4 itself, folded into the code column and copied verbatim; a row with no footnote means the filing has none.
Guide: Insider buying · all guides
What is behind these trades
The concepts on this page, explained from scratch in the Academy. Free, no account.
- What the efficiency hypothesis says and what it does NOT sayIf an insider's purchase is public and anyone can read it, is there any information left in it? That is the exact question that brings people here.
- Who really moves the market: the types of investorWho sits on the other side of each order, and where a company's own insiders fit among them.
- Supply, demand and price: why it rises and falls constantlyHow a piece of news ends up inside the price, and why the reaction to a filed sale is rarely the one you would expect.
Source: SEC EDGAR Form 4. This is a list of public facts, not financial advice or a recommendation to buy or sell.