Plan Ledger DOL Form 5500 · updated monthly

Seres Therapeutics, Inc.401(k)

SERES THERAPEUTICS, INC. 401(K) PLAN · CAMBRIDGE, MA · plan year 2025

Reported admin expense ratio · 2025
0.01%

Peer grade: A · admin costs + employer contributions vs same-size plans · how grading works

Seres Therapeutics, Inc. reported $2,417 in plan administrative expenses for 2025: 0.01% of average plan assets, lower than ~75% of peers. Employer contributions averaged $8,839 per active participant. This ratio covers administrative expenses reported on the plan's Schedule H only; fund-level expense ratios are not included in public structured data — see methodology.

Across the 3 years on file its reported administrative ratio fell from 0.007% to 0.006%. The plan sits in the $10M–$50M size bracket, benchmarked here against 1,620 comparable plans and shown alongside other information & media employers. By assets it is the 772nd-largest of 2,726 plans among Massachusetts employers on file, and the 584th of 2,199 in information & media. In 2025, employees put in $2.90 for every $1.00 the employer contributed; active participation has shrunk from 419 to 67 since 2022.

Plan summary
Net assets, end of year$43,581,880
Participants with balances336
Active participants67
Employer contributions$592,186
Employee contributions$1,714,959
Employer contribution per active participant$8,839
Average account balance$129,708
Benefits paid to participants$5,974,481
Plan auditUnmodified (clean) audit opinion
Plan history4
Yearassets · accounts · employer contribution
2025$43.6M · 336 accts · $592K emplr
2024$39.1M · 403 accts · $1.1M emplr
2023$39.3M · 375 accts · $2.0M emplr
2022$26.7M · 515 accts · $1.8M emplr
Administrative expenses, itemized · 2025
Recordkeeping & contract admin$2,417
Total administrative$2,417
The Seres Therapeutics, Inc. 401(k) match · 2025
Employer contribution per active participant$8,839
Median for plans this size$2,666
2025$8,839 per active participant
2024$10,154 per active participant
2023$8,206 per active participant
2022$4,225 per active participant

Seres Therapeutics, Inc.'s 2025 employer contribution ran above the $2,666 median for plans its size, placing it in the top quarter of its peers. Filings report dollars actually contributed, not the match formula; the formula itself (for example, 50% of the first 6% of pay) lives in the plan's summary plan description from HR.

What these fees cost you

Annual cost at the plan's reported 2025 administrative ratio, against the median plan its size; fund expense ratios are extra. Compare any plan.

Service providers · 20251
FIDELITY INVESTMENTS INSTITUTIONAL · Loan processing$2,417

Compensation shown is direct payments from plan assets reported on Schedule C. Providers paid through fund revenue-sharing appear as indirect.

Administrative cost history4
2025$2,417 · 0.01%
2024$4,215 · 0.01%
2023$16,282 · 0.05%
2022$1,806 · 0.01%
Same employer
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Definitive Healthcare, LLC MA$51.5M · 0.03%
Recorded Future, Inc. MA$46.9M · 0.41%
Ibasis, Inc. MA$46.6M · 0.03%
Interactions, LLC MA$37.5M · 0.15%
Salsify, Inc MA$37.5M · 0.24%

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Source: U.S. Department of Labor, Form 5500 series, EIN 274326290 · Verify on EFAST2 · Amounts are as reported by the plan sponsor for the plan year shown.