Alnylam Pharmaceuticals, Inc. 401(k) Plan: Login, Facts & Contact Information

Alnylam Pharmaceuticals, Inc. 401(k) Plan Facts

Plan name
ALNYLAM PHARMACEUTICALS, INC. SAVINGS & INVESTMENT PLAN
Plan type
401(k) with employer contributions
Plan sponsor
ALNYLAM PHARMACEUTICALS, INC.
Participants
2,199 (1,815 active employees)
Former employees with a balance
587
Plan assets
$343,996,084 at Dec 31, 2024
Average account balance
$148,019 across 2,324 accounts
Employer contributions
$14,660,673 in plan year 2024 (25% of all contributions)
Recordkeeper
Fidelity Investments Institutional
Plan year
Jan 1, 2024 – Dec 31, 2024
Plan established
Jan 1, 2003
Employer contributions Automatic enrollment Default investment for undecided participants Participants choose their own investments Self-directed brokerage window Profit sharing Company stock (ESOP)

Source: Form 5500 for plan year 2024 (Jan 1, 2024 – Dec 31, 2024), filed Oct 10, 2025. Public filing with the U.S. Department of Labor.

Money in and out in plan year 2024

  • $59.7 million went into the plan in contributions, $14.7 million of it from the employer (25%).
  • $38.7 million was paid out to participants.
  • Investment and other income added $47.8 million.
  • Administrative expenses were $361,760, about $156 per account.

How the Alnylam Pharmaceuticals, Inc. 401(k) changed, 20192024

Plan yearParticipantsPlan assetsEmployer contributionsBenefits paid
20191,052$114.0 million$4.05 million$8.02 million
20201,307$159.9 million$7.47 million$9.94 million
20211,464$213.7 million$8.27 million$12.4 million
20221,721$210.2 million$9.53 million$15.9 million
20232,090$275.6 million$11.2 million$15.2 million
20242,199$344.0 million$14.7 million$38.7 million

Alnylam Pharmaceuticals, Inc. 401(k) Contact Information

Phone
617-551-8342
Mailing address
300 THIRD STREET 3RD FLOOR, CAMBRIDGE MA 02142
Plan sponsor
ALNYLAM PHARMACEUTICALS, INC.
Employer identification number (EIN)
04-3696884
Plan number
001

Questions about the Alnylam Pharmaceuticals, Inc. 401(k)

Does Alnylam Pharmaceuticals, Inc contribute to the 401(k)?

Yes. The plan reports an employer contribution arrangement. In plan year 2024 the employer contributed $14.7 million, 25% of all contributions.

Does the Alnylam Pharmaceuticals, Inc 401(k) have automatic enrollment?

No. The plan does not report automatic enrollment; employees enroll themselves.

How many people are in the Alnylam Pharmaceuticals, Inc 401(k) plan?

2,199 participants at the start of plan year 2024, 1,815 of them active employees, and 587 former employees who still had money in the plan.

What is the average 401(k) balance at Alnylam Pharmaceuticals, Inc?

About $148,019 per account: $344.0 million in plan assets across 2,324 accounts with a balance at the end of plan year 2024.

Who manages the Alnylam Pharmaceuticals, Inc 401(k) accounts?

Fidelity NetBenefits (listed on the filing as FIDELITY INVESTMENTS INSTITUTIONAL) is the plan's recordkeeper, which is where participants log in to see their balance.

I no longer work at Alnylam Pharmaceuticals, Inc. How do I access my 401(k)?

Your account stays with Fidelity NetBenefits after you leave, so you can log in with the same credentials. If your balance was small, the plan may have rolled it into an IRA in your name. If you can't find it, Beagle can locate it for you.

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