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AON PLC

Holders

4

Combined Value

$646.69M

Combined Shares

2,003,515

Investor Activity Chart

Quarterly buys (▲) and sells (▼) by tracked investors. Click a marker to view that investor's portfolio; hover for details. Price line is implied from 13F filings (value ÷ shares), not market data.

$272.48$321.72$370.95$420.19Q2'24Q3'24Q4'24Q1'25Q2'25Q3'25Q4'25Q1'26Q2 2024 · implied price $293.58Q3 2024 · implied price $345.99Q4 2024 · implied price $359.16Q1 2025 · implied price $399.09Q2 2025 · implied price $356.76Q3 2025 · implied price $356.58Q4 2025 · implied price $352.88Q1 2026 · implied price $322.78Warren Buffett - Berkshire Hathaway · bought 4,100,000 shares @ ~$293.58 · Q2 2024 (new position)Tom Gayner - Markel Group · bought 113,950 shares @ ~$293.58 · Q2 2024 (new position)Jim Simons - Renaissance Technologies · bought 78,001 shares @ ~$293.58 · Q2 2024 (new position)Tom Gayner - Markel Group · bought 4,250 shares @ ~$352.88 · Q4 2025Andreas Halvorsen - Viking Global Investors · sold 630,968 shares @ ~$352.88 · Q4 2025Warren Buffett - Berkshire Hathaway · sold 497,005 shares @ ~$352.88 · Q4 2025Harris Associates (Oakmark Funds) · sold 5 shares @ ~$352.88 · Q4 2025Seth Klarman - Baupost Group · bought 769,000 shares @ ~$322.78 · Q1 2026 (new position)Andreas Halvorsen - Viking Global Investors · bought 303,464 shares @ ~$322.78 · Q1 2026Jim Simons - Renaissance Technologies · bought 11,601 shares @ ~$322.78 · Q1 2026 (new position)Tom Gayner - Markel Group · bought 1,750 shares @ ~$322.78 · Q1 2026Warren Buffett - Berkshire Hathaway · sold 3,602,995 shares @ ~$352.88 · Q1 2026 (sold out)Harris Associates (Oakmark Funds) · sold 699 shares @ ~$352.88 · Q1 2026 (sold out)Andreas Halvorsen - Viking Global Investors · bought 563,027 shares @ ~$345.99 · Q3 2024 (new position)Jim Simons - Renaissance Technologies · bought 103,300 shares @ ~$345.99 · Q3 2024Tom Gayner - Markel Group · bought 6,200 shares @ ~$345.99 · Q3 2024Andreas Halvorsen - Viking Global Investors · bought 157,337 shares @ ~$359.16 · Q4 2024Tom Gayner - Markel Group · bought 6,050 shares @ ~$359.16 · Q4 2024Jim Simons - Renaissance Technologies · sold 43,900 shares @ ~$359.16 · Q4 2024Tom Gayner - Markel Group · bought 3,250 shares @ ~$399.09 · Q1 2025Andreas Halvorsen - Viking Global Investors · sold 720,364 shares @ ~$359.16 · Q1 2025 (sold out)Jim Simons - Renaissance Technologies · sold 102,300 shares @ ~$399.09 · Q1 2025Harris Associates (Oakmark Funds) · bought 699 shares @ ~$356.76 · Q2 2025 (new position)Tom Gayner - Markel Group · bought 350 shares @ ~$356.76 · Q2 2025Jim Simons - Renaissance Technologies · sold 35,101 shares @ ~$399.09 · Q2 2025 (sold out)Andreas Halvorsen - Viking Global Investors · bought 1,414,618 shares @ ~$356.58 · Q3 2025 (new position)Harris Associates (Oakmark Funds) · bought 5 shares @ ~$356.58 · Q3 2025BUYSELLIMPLIED PRICE

Held By

Tracked investors currently holding this security, based on each investor's most recent 13F filing. Gain compares the current market price to each investor's estimated average buy price.

InvestorValue% of PortfolioAvg Buy PriceGainLast ActivityAs of
Andreas Halvorsen - Viking Global Investors$350.90M0.98%~$347.14—BUY Q1 2026Q1 2026
Seth Klarman - Baupost Group$248.22M4.85%~$322.78—BUY Q1 2026Q1 2026
Tom Gayner - Markel Group$43.83M0.37%~$303.81—BUY Q1 2026Q1 2026
Jim Simons - Renaissance Technologies$3.74M0.01%~$322.78—BUY Q1 2026Q1 2026

Recent Activity

Latest position changes by tracked investors. Prices are estimates implied from 13F filings.

QuarterInvestorActionEst. ValueEst. Price
Q1 2026Warren Buffett - Berkshire HathawaySOLD OUT−$1.27B~$352.88
Q1 2026Seth Klarman - Baupost GroupNEW BUY+$248.22M~$322.78
Q1 2026Andreas Halvorsen - Viking Global InvestorsBUY+$97.95M~$322.78
Q1 2026Jim Simons - Renaissance TechnologiesNEW BUY+$3.74M~$322.78
Q1 2026Tom Gayner - Markel GroupBUY+$564.9K~$322.78
Q1 2026Harris Associates (Oakmark Funds)SOLD OUT−$246.7K~$352.88
Q4 2025Andreas Halvorsen - Viking Global InvestorsSELL−$222.66M~$352.88
Q4 2025Warren Buffett - Berkshire HathawaySELL−$175.38M~$352.88
Q4 2025Tom Gayner - Markel GroupBUY+$1.50M~$352.88
Q4 2025Harris Associates (Oakmark Funds)SELL−$1.8K~$352.88
Q3 2025Andreas Halvorsen - Viking Global InvestorsNEW BUY+$504.42M~$356.58
Q3 2025Harris Associates (Oakmark Funds)BUY+$1.8K~$356.58
Q2 2025Jim Simons - Renaissance TechnologiesSOLD OUT−$14.01M~$399.09
Q2 2025Harris Associates (Oakmark Funds)NEW BUY+$249.4K~$356.76
Q2 2025Tom Gayner - Markel GroupBUY+$124.9K~$356.76
Q1 2025Andreas Halvorsen - Viking Global InvestorsSOLD OUT−$258.73M~$359.16
Q1 2025Jim Simons - Renaissance TechnologiesSELL−$40.83M~$399.09
Q1 2025Tom Gayner - Markel GroupBUY+$1.30M~$399.09
Q4 2024Andreas Halvorsen - Viking Global InvestorsBUY+$56.51M~$359.16
Q4 2024Jim Simons - Renaissance TechnologiesSELL−$15.77M~$359.16
Q4 2024Tom Gayner - Markel GroupBUY+$2.17M~$359.16
Q3 2024Andreas Halvorsen - Viking Global InvestorsNEW BUY+$194.80M~$345.99
Q3 2024Jim Simons - Renaissance TechnologiesBUY+$35.74M~$345.99
Q3 2024Tom Gayner - Markel GroupBUY+$2.15M~$345.99
Q2 2024Warren Buffett - Berkshire HathawayNEW BUY+$1.20B~$293.58

Ownership History

Aggregate position across all tracked investors per quarter (options excluded). Implied price is the reported value divided by shares held.

PeriodHoldersTotal SharesΔ SharesTotal ValueImplied Price
Q1 202642,003,515-55.7%$646.69M$322.78
Q4 202544,521,394-19.9%$1.60B$352.88
Q3 202545,645,122+33.4%$2.01B$356.58
Q2 202534,230,499-0.8%$1.51B$356.76
Q1 202534,264,551-16.1%$1.70B$399.09
Q4 202445,083,965+2.4%$1.83B$359.16
Q3 202444,964,478+15.7%$1.72B$345.99
Q2 202434,291,951—$1.26B$293.58