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MFS INSTITUTIONAL ADVISORS INC.
CRD 107144File 801-46433
APPROVED
Retail clients
Custody
Disclosure events
Filing as of Mar 31, 2026
Feed vintage Oct 1, 2026
Regulatory AUM
$113.59B
Top 10% of cohort (national)
Discretionary AUM
$113.59B
Clients
10,261
13,555 accounts
Employees
1,311
Top 10% of cohort in MA
Identity & registration
ADV Item 1- Organization form
- Corporation
- Firm type
- Registered
- SEC region
- BRO
- Registration date
- May 6, 1994
- Principal office
- 111 HUNTINGTON AVENUE, BOSTON, MA, 02199-7618
- Phone
- 617-954-5000
- Website
- http://www.mfs.com
Assets & accounts
ADV Item 5F- Total regulatory AUM
- $113.59B
- Discretionary AUM
- $113.59B
- Non-discretionary AUM
- $0
- Discretionary accounts
- 13,555
- Non-discretionary accounts
- 0
- Total accounts
- 13,555
- AUM per client
- $11.1M
Clients by type
ADV Item 5D| Client type | Clients | AUM |
|---|---|---|
| Other | 114 | $606.3M |
| Non-U.S. persons | 12 | $14.56B |
| Insurance companies | 37 | $7.79B |
| Investment companies | 2 | $748.6M |
| Charitable organizations | 116 | $1.85B |
| High net worth individuals | 407 | $1.02B |
| Pooled investment vehicles | 124 | $45.97B |
| Pension and profit sharing plans | 253 | $17.01B |
| State or municipal government entities | 51 | $19.67B |
| Individuals (other than high net worth individuals) | 9,145 | $2.18B |
Compensation & activities
ADV Items 5E, 5GCompensation
- Other
- Other (described) — TRANSFER PRICING ARRANGEMENTS WITH AFFILIATES
- Performance-based fees
- A percentage of assets under your management
Advisory activities
- Selection of other advisers
- Portfolio management for other
- Portfolio management for businesses
- Portfolio management for investment companies
- Portfolio management for pooled investment vehicles
- Portfolio management for individuals and/or small businesses
Custody
ADV Item 9- Firm Custody Cash
- Yes
- Firm Custody Assets
- Yes
- Firm Custody Clients
- Yes
- Firm Custody Securities
- Yes
- Related Person Custody Cash
- No
- Related Person Custody Assets
- No
- Related Person Custody Clients
- No
- Related Person Custody Securities
- Yes
Disclosure events
ADV Item 11- Q11C1
- Q11C2
- Q11C4
- Q11C5
Filed changes
| Date | Field | From | To | Change |
|---|---|---|---|---|
| Aug 17, 2026 | Clients | 13,555 | 10,261 | decreased by3,294 |
| Apr 1, 2026 | Employees | 1,331 | 1,311 | decreased by20 |
| Apr 1, 2026 | Clients | 10,260 | 13,555 | increased by3,295 |
| Apr 1, 2026 | AUM | $111,845,233,320 | $113,585,882,234 | increased by$1,740,648,914 |
| Apr 1, 2026 | Accounts | 10,260 | 13,555 | increased by3,295 |
| May 1, 2025 vs Oct 1, 2022 | Employees | 1,200 | 1,331 | increased by131 |
| May 1, 2025 vs Oct 1, 2022 | Clients | 6,816 | 10,260 | increased by3,444 |
| May 1, 2025 vs Oct 1, 2022 | AUM | $146,411,056,016 | $111,845,233,320 | decreased by$34,565,822,696 |
| May 1, 2025 vs Oct 1, 2022 | Accounts | 6,816 | 10,260 | increased by3,444 |
| Apr 1, 2022 | Employees | 1,500 | 1,200 | decreased by300 |
| Apr 1, 2022 | Clients | 8,126 | 6,816 | decreased by1,310 |
| Apr 1, 2022 | AUM | $134,339,947,746 | $146,411,056,016 | increased by$12,071,108,270 |
| Apr 1, 2022 | Accounts | 8,126 | 6,816 | decreased by1,310 |
| Apr 1, 2021 | Registration | — | APPROVED |
On Form 5500, an adviser usually appears as a plan service provider (Schedule C), not the plan sponsor.
See plans that list “MFS INSTITUTIONAL” as a service provider on 5500mcp →Matched by name only — Form ADV and Form 5500 share no identifier, and names are searched loosely (“MFS INSTITUTIONAL” may also match similarly-named firms). Confirm identity against each filing.
Every value above is reproduced from this firm's Form ADV filing. Fields the firm left blank are shown as “Not reported” rather than filled in from other sources.