Aon 401(k) and pension plans

Aon Corporation, Atlanta, GA. EIN 36-3051915. Annual reports 2009–2025.

Aon Corporation has 2 active retirement plans on file. The largest is the Aon Savings Plan, with 24,043 participants and $7.4 billion in assets in 2025. Vanguard is its recordkeeper.

Active plans: 2
Participants: 37,641
Plan assets: $8.8 billion
401(k) recordkeeper: Vanguard
Plans on file: 4
Industry: Finance and insurance

All 4 plans

Active plans first

Aon Savings Plan

401(k)Active

Active. The plan filed its annual report for the 2025 plan year.

Plan number: 020Employer EIN 36-3051915
Participants (2025): 24,043
Net assets (2025): $7.4 billion
Recordkeeper: VanguardEarlier: Alight (2012–2024), ING Retirement Services (2009–2011)
Plan administrator: Administrative Committee
MSC# 17755, P.O. Box 551343
Atlanta, GA 30355
(312) 381-1000As filed for 2025
In effect since: July 1, 1984

Plans merged into this one: Benfield Retirement Plan (2009).

Year by year, 2009 to 2025

Plan year	Participants	Net assets	Recordkeeper
2025	24,043	$7.4 billion	Vanguard
2024	24,731	$6.6 billion	Alight
2023	25,092	$6.1 billion	Alight
2022	25,261	$5.3 billion	Alight
2021	23,894	$6.5 billion	Alight
2020	23,976	$5.8 billion	Alight
2019	24,153	$5.2 billion	Alight
2018	27,232	$4.4 billion	Alight
2017	28,892	$4.7 billion	Alight
2016	40,312	$5.3 billion	Alight
2015	40,533	$4.9 billion	Alight
2014	37,797	$4.9 billion	Alight
2013	36,185	$4.6 billion	Alight
2012	36,352	$3.8 billion	Alight
2011	19,724	$3.3 billion	ING Retirement Services
2010	19,174	$1.8 billion	ING Retirement Services
2009	20,409	$1.6 billion	ING Retirement Services

Aon Retirement Pension Plan

Cash balance pension, frozenActive

Active. The plan filed its annual report for the 2024 plan year.

Plan number: 090Employer EIN 36-3051915
Participants (2024): 13,598
Net assets (2024): $1.4 billion
Last listed administrator: Alight2022
Plan administrator: Administrative Committee
MSC# 17755, Po Box 551343
Atlanta, GA 30355
(312) 381-1000As filed for 2024
In effect since: January 1, 2020

Plans merged into this one: Aon Pension Plan (2022).

Year by year, 2020 to 2024

Plan year	Participants	Net assets	Recordkeeper
2024	13,598	$1.4 billion	not listed
2023	13,770	$1.5 billion	not listed
2022	13,897	$1.5 billion	Alight
2021	18,409	$2.3 billion	not listed
2020	18,622	$2.2 billion	not listed

Aon Pension Plan

Cash balance pension, frozenMerged

Merged. In 2022 its assets moved to the Aon Retirement Pension Plan, sponsored by Aon Corporation (EIN 36-3051915, plan 090). Accounts moved with them, so that plan is the one to contact.

Plan number: 010Employer EIN 36-3051915
Participants (2021): 5,169
Net assets (2021): $118 million
Last listed administrator: Alight2012–2019
Plan administrator: Administrative Committee
MSC# 17755, Po Box 1447
Lincolnshire, IL 60069
(312) 381-1000As filed for 2022
In effect since: January 1, 1973

Year by year, 2009 to 2022

Plan year	Participants	Net assets	Recordkeeper
2022	0	$0	not listed
2021	5,169	$118 million	not listed
2020	5,365	$128 million	not listed
2019	24,455	$2.1 billion	Alight
2018	24,817	$1.8 billion	Alight
2017	25,222	$2.1 billion	Alight
2016	25,538	$1.8 billion	Alight
2015	31,708	$2.0 billion	Alight
2014	33,016	$2.1 billion	Alight
2013	33,382	$1.9 billion	Alight
2012	34,088	$1.7 billion	Alight
2011	34,262	$1.5 billion	not listed
2010	34,385	$1.3 billion	not listed
2009	34,606	$1.2 billion	not listed

Benfield Retirement Plan

401(k)Merged

Merged. In 2009 its assets moved to the Aon Savings Plan, sponsored by Aon Corporation (EIN 36-3051915, plan 020). Accounts moved with them, so that plan is the one to contact.

Plan number: 001Employer EIN 36-3051915
Plan administrator: Aon Corporation
200 E. Randolph Street, 5TH Floor
Chicago, IL 60601
(312) 381-1000As filed for 2009
In effect since: September 1, 1985

If you had money in one of these plans

Call Vanguard (investor.vanguard.com), which runs the Aon Savings Plan. With your Social Security number and the plan name, it can tell you whether you still have a balance and, if not, where it went.
Or call the plan administrator listed on the plan below ((312) 381-1000). That number was filed for 2025; ask for the benefits or retirement plan office.
If your plan was merged, your account moved with it. Follow the link on the plan to the plan it went into, and contact that one.
Still stuck? The Department of Labor's benefits advisers help for free: askebsa.dol.gov or 1-866-444-3272. Never pay anyone to find your own money.

What these numbers are

They come from the Form 5500 annual reports each plan files with the Department of Labor, as the plan filed them. A plan year is usually a calendar year.
Participants counts everyone in the plan at year end: current employees, former employees who still have a balance or a pension coming, and retirees or beneficiaries being paid.
The recordkeeper is the service provider whose Schedule C entry says it keeps the plan's records. Small plans do not file Schedule C, so some plans show none.
We cannot see anyone's account. Only the plan or its recordkeeper can tell you your balance.

Sources: U.S. Department of Labor, Form 5500 datasets and PBGC trusteed plans. How we read them.