The Middlesex Corporation
Plan context: The Middlesex Corporation Retirement Savings Plan
EIN 04-2534615 • Littleton, MA • 52 filings • 8 plans
Current Snapshot
Latest Year
2024
2024 Participants
887
2024 Assets
$117,897,915
2024 Contributions
$17,024,817
Historical Graphs
Total Assets Over Time
Aggregate end-of-year assets by filing year, excluding zero-asset years
Participants Over Time
Largest reported end-of-year plan headcount by filing year, used to avoid double-counting participants across overlapping plans
Company Timeline
Year summaries and individual filings are combined here so you can stay in one place while moving across years and plan filings.
| Year / Filing | Filings | Participants | Assets | Contributions | Contrib./Participant |
|---|---|---|---|---|---|
| 2024 | 2 | 887 | $117,897,915 | $17,024,817 | $19,194iApproximate average salary by contribution assumption: employee only about $479,843 at 4% or $319,895 at 6%; with 50% employer match about $319,895 at 4% or $213,263 at 6%; with 100% employer match about $239,921 at 4% or $159,948 at 6%. |
| The Middlesex Corporation Retirement Savings Plan | - | 887 | $117,897,915 | $17,024,817 | $19,194iApproximate average salary by contribution assumption: employee only about $479,843 at 4% or $319,895 at 6%; with 50% employer match about $319,895 at 4% or $213,263 at 6%; with 100% employer match about $239,921 at 4% or $159,948 at 6%. |
| The Middlesex Corporation Health Benefit Plan | - | 783 | - | - | - |
| 2023 | 2 | 810 | $102,656,093 | $12,445,347 | $15,365iApproximate average salary by contribution assumption: employee only about $384,116 at 4% or $256,077 at 6%; with 50% employer match about $256,077 at 4% or $170,718 at 6%; with 100% employer match about $192,058 at 4% or $128,039 at 6%. |
| The Middlesex Corporation Retirement Savings Plan | - | 810 | $102,656,093 | $12,445,347 | $15,365iApproximate average salary by contribution assumption: employee only about $384,116 at 4% or $256,077 at 6%; with 50% employer match about $256,077 at 4% or $170,718 at 6%; with 100% employer match about $192,058 at 4% or $128,039 at 6%. |
| The Middlesex Corporation Health Benefit Plan | - | 769 | - | - | - |
| 2022 | 2 | 903 | $86,944,368 | $12,208,552 | $13,520iApproximate average salary by contribution assumption: employee only about $338,000 at 4% or $225,333 at 6%; with 50% employer match about $225,333 at 4% or $150,222 at 6%; with 100% employer match about $169,000 at 4% or $112,667 at 6%. |
| The Middlesex Corporation Retirement Savings Plan | - | 772 | $86,944,368 | $12,208,552 | $15,814iApproximate average salary by contribution assumption: employee only about $395,355 at 4% or $263,570 at 6%; with 50% employer match about $263,570 at 4% or $175,713 at 6%; with 100% employer match about $197,677 at 4% or $131,785 at 6%. |
| The Middlesex Corporation Health Benefit Plan | - | 903 | - | - | - |
| 2021 | 2 | 903 | $108,974,174 | $14,890,537 | $16,490iApproximate average salary by contribution assumption: employee only about $412,252 at 4% or $274,835 at 6%; with 50% employer match about $274,835 at 4% or $183,223 at 6%; with 100% employer match about $206,126 at 4% or $137,417 at 6%. |
| The Middlesex Corporation Retirement Savings Plan | - | 868 | $108,974,174 | $14,890,537 | $17,155iApproximate average salary by contribution assumption: employee only about $428,875 at 4% or $285,917 at 6%; with 50% employer match about $285,917 at 4% or $190,611 at 6%; with 100% employer match about $214,437 at 4% or $142,958 at 6%. |
| The Middlesex Corporation Health Benefit Plan | - | 903 | - | - | - |
| 2020 | 2 | 957 | $95,696,183 | $16,350,077 | $17,085iApproximate average salary by contribution assumption: employee only about $427,118 at 4% or $284,745 at 6%; with 50% employer match about $284,745 at 4% or $189,830 at 6%; with 100% employer match about $213,559 at 4% or $142,373 at 6%. |
| The Middlesex Corporation Retirement Savings Plan | - | 957 | $95,696,183 | $16,350,077 | $17,085iApproximate average salary by contribution assumption: employee only about $427,118 at 4% or $284,745 at 6%; with 50% employer match about $284,745 at 4% or $189,830 at 6%; with 100% employer match about $213,559 at 4% or $142,373 at 6%. |
| The Middlesex Corporation Health Benefit Plan | - | 879 | - | - | - |
| 2019 | 2 | 1,009 | $75,085,301 | $11,440,674 | $11,339iApproximate average salary by contribution assumption: employee only about $283,466 at 4% or $188,977 at 6%; with 50% employer match about $188,977 at 4% or $125,985 at 6%; with 100% employer match about $141,733 at 4% or $94,489 at 6%. |
| The Middlesex Corporation Retirement Savings Plan | - | 1,009 | $75,085,301 | $11,440,674 | $11,339iApproximate average salary by contribution assumption: employee only about $283,466 at 4% or $188,977 at 6%; with 50% employer match about $188,977 at 4% or $125,985 at 6%; with 100% employer match about $141,733 at 4% or $94,489 at 6%. |
| The Middlesex Corporation Health Benefit Plan | - | 963 | - | - | - |
| 2018 | 2 | 932 | $60,094,039 | $8,731,395 | $9,368iApproximate average salary by contribution assumption: employee only about $234,211 at 4% or $156,141 at 6%; with 50% employer match about $156,141 at 4% or $104,094 at 6%; with 100% employer match about $117,106 at 4% or $78,070 at 6%. |
| The Middlesex Corporation Retirement Savings Plan | - | 932 | $60,094,039 | $8,731,395 | $9,368iApproximate average salary by contribution assumption: employee only about $234,211 at 4% or $156,141 at 6%; with 50% employer match about $156,141 at 4% or $104,094 at 6%; with 100% employer match about $117,106 at 4% or $78,070 at 6%. |
| The Middlesex Corporation Health Benefit Plan | - | 444 | - | - | - |
| 2017 | 2 | 937 | $58,146,432 | $7,441,690 | $7,942iApproximate average salary by contribution assumption: employee only about $198,551 at 4% or $132,367 at 6%; with 50% employer match about $132,367 at 4% or $88,245 at 6%; with 100% employer match about $99,275 at 4% or $66,184 at 6%. |
| The Middlesex Corporation Retirement Savings Plan | - | 934 | $58,146,432 | $7,441,690 | $7,968iApproximate average salary by contribution assumption: employee only about $199,189 at 4% or $132,792 at 6%; with 50% employer match about $132,792 at 4% or $88,528 at 6%; with 100% employer match about $99,594 at 4% or $66,396 at 6%. |
| The Middlesex Corporation Health Benefit Plan | - | 937 | - | - | - |
| 2016 | 2 | 846 | $46,747,238 | $6,850,592 | $8,098iApproximate average salary by contribution assumption: employee only about $202,441 at 4% or $134,960 at 6%; with 50% employer match about $134,960 at 4% or $89,974 at 6%; with 100% employer match about $101,220 at 4% or $67,480 at 6%. |
| The Middlesex Corporation Retirement Savings Plan | - | 846 | $46,747,238 | $6,850,592 | $8,098iApproximate average salary by contribution assumption: employee only about $202,441 at 4% or $134,960 at 6%; with 50% employer match about $134,960 at 4% or $89,974 at 6%; with 100% employer match about $101,220 at 4% or $67,480 at 6%. |
| The Middlesex Corporation Health Benefit Plan | - | 788 | - | - | - |
| 2015 | 2 | 688 | $39,524,522 | $4,814,534 | $6,998iApproximate average salary by contribution assumption: employee only about $174,947 at 4% or $116,631 at 6%; with 50% employer match about $116,631 at 4% or $77,754 at 6%; with 100% employer match about $87,473 at 4% or $58,316 at 6%. |
| The Middlesex Corporation Retirement Savings Plan | - | 688 | $39,524,522 | $4,814,534 | $6,998iApproximate average salary by contribution assumption: employee only about $174,947 at 4% or $116,631 at 6%; with 50% employer match about $116,631 at 4% or $77,754 at 6%; with 100% employer match about $87,473 at 4% or $58,316 at 6%. |
| The Middlesex Corporation Health Benefit Plan | - | 406 | - | - | - |
| 2014 | 2 | 554 | $39,978,853 | $5,330,890 | $9,623iApproximate average salary by contribution assumption: employee only about $240,564 at 4% or $160,376 at 6%; with 50% employer match about $160,376 at 4% or $106,917 at 6%; with 100% employer match about $120,282 at 4% or $80,188 at 6%. |
| The Middlesex Corporation Retirement Savings Plan | - | 554 | $39,978,853 | $5,330,890 | $9,623iApproximate average salary by contribution assumption: employee only about $240,564 at 4% or $160,376 at 6%; with 50% employer match about $160,376 at 4% or $106,917 at 6%; with 100% employer match about $120,282 at 4% or $80,188 at 6%. |
| The Middlesex Corporation Health Benefit Plan | - | 306 | - | - | - |
| 2013 | 2 | 505 | $34,650,688 | $4,713,603 | $9,334iApproximate average salary by contribution assumption: employee only about $233,347 at 4% or $155,564 at 6%; with 50% employer match about $155,564 at 4% or $103,710 at 6%; with 100% employer match about $116,673 at 4% or $77,782 at 6%. |
| The Middlesex Corporation Retirement Savings Plan | - | 505 | $34,650,688 | $4,713,603 | $9,334iApproximate average salary by contribution assumption: employee only about $233,347 at 4% or $155,564 at 6%; with 50% employer match about $155,564 at 4% or $103,710 at 6%; with 100% employer match about $116,673 at 4% or $77,782 at 6%. |
| The Middlesex Corporation Health Benefit Plan | - | 445 | - | - | - |
| 2012 | 2 | 473 | $26,065,468 | $3,615,500 | $7,644iApproximate average salary by contribution assumption: employee only about $191,094 at 4% or $127,396 at 6%; with 50% employer match about $127,396 at 4% or $84,931 at 6%; with 100% employer match about $95,547 at 4% or $63,698 at 6%. |
| The Middlesex Corporation Retirement Savings Plan | - | 473 | $26,065,468 | $3,615,500 | $7,644iApproximate average salary by contribution assumption: employee only about $191,094 at 4% or $127,396 at 6%; with 50% employer match about $127,396 at 4% or $84,931 at 6%; with 100% employer match about $95,547 at 4% or $63,698 at 6%. |
| The Middlesex Corporation Health Benefit Plan | - | 432 | - | - | - |
| 2011 | 3 | 403 | $20,557,973 | $2,600,310 | $6,452iApproximate average salary by contribution assumption: employee only about $161,310 at 4% or $107,540 at 6%; with 50% employer match about $107,540 at 4% or $71,693 at 6%; with 100% employer match about $80,655 at 4% or $53,770 at 6%. |
| The Middlesex Corporation Retirement Savings Plan | - | 403 | $20,557,973 | $2,600,310 | $6,452iApproximate average salary by contribution assumption: employee only about $161,310 at 4% or $107,540 at 6%; with 50% employer match about $107,540 at 4% or $71,693 at 6%; with 100% employer match about $80,655 at 4% or $53,770 at 6%. |
| The Middlesex Corporation Health Benefit Plan | - | 366 | - | - | - |
| The Middlesex Corporation Health Benefit Plan | - | 384 | - | - | - |
| 2010 | 2 | 342 | $19,130,804 | $2,519,747 | $7,368iApproximate average salary by contribution assumption: employee only about $184,192 at 4% or $122,795 at 6%; with 50% employer match about $122,795 at 4% or $81,863 at 6%; with 100% employer match about $92,096 at 4% or $61,397 at 6%. |
| The Middlesex Corporation Retirement Savings Plan | - | 328 | $19,130,804 | $2,519,747 | $7,682iApproximate average salary by contribution assumption: employee only about $192,054 at 4% or $128,036 at 6%; with 50% employer match about $128,036 at 4% or $85,357 at 6%; with 100% employer match about $96,027 at 4% or $64,018 at 6%. |
| The Middlesex Corporation Health Benefit Plan | - | 342 | - | - | - |
| 2009 | 2 | 315 | $15,141,582 | $1,884,712 | $5,983iApproximate average salary by contribution assumption: employee only about $149,580 at 4% or $99,720 at 6%; with 50% employer match about $99,720 at 4% or $66,480 at 6%; with 100% employer match about $74,790 at 4% or $49,860 at 6%. |
| The Middlesex Corporation Retirement Savings Plan | - | 287 | $15,141,582 | $1,884,712 | $6,567iApproximate average salary by contribution assumption: employee only about $164,174 at 4% or $109,449 at 6%; with 50% employer match about $109,449 at 4% or $72,966 at 6%; with 100% employer match about $82,087 at 4% or $54,725 at 6%. |
| The Middlesex Corporation Health Benefit Plan | - | 315 | - | - | - |
| 2008 | 2 | 526 | $11,104,430 | $1,732,518 | $3,294iApproximate average salary by contribution assumption: employee only about $82,344 at 4% or $54,896 at 6%; with 50% employer match about $54,896 at 4% or $36,597 at 6%; with 100% employer match about $41,172 at 4% or $27,448 at 6%. |
| The Middlesex Corporation Retirement Savings Plan | - | 526 | $11,104,430 | $1,732,518 | $3,294iApproximate average salary by contribution assumption: employee only about $82,344 at 4% or $54,896 at 6%; with 50% employer match about $54,896 at 4% or $36,597 at 6%; with 100% employer match about $41,172 at 4% or $27,448 at 6%. |
| The Middlesex Corporation Health Benefit Plan | - | 271 | - | - | - |
| 2007 | 2 | 659 | $15,147,532 | $1,844,196 | $2,798iApproximate average salary by contribution assumption: employee only about $69,962 at 4% or $46,641 at 6%; with 50% employer match about $46,641 at 4% or $31,094 at 6%; with 100% employer match about $34,981 at 4% or $23,321 at 6%. |
| The Middlesex Corporation Retirement Savings Plan | - | 659 | $15,147,532 | $1,844,196 | $2,798iApproximate average salary by contribution assumption: employee only about $69,962 at 4% or $46,641 at 6%; with 50% employer match about $46,641 at 4% or $31,094 at 6%; with 100% employer match about $34,981 at 4% or $23,321 at 6%. |
| The Middlesex Corporation Health Benefit Plan | - | 356 | - | - | - |
| 2006 | 2 | 766 | $14,227,369 | $2,087,627 | $2,725iApproximate average salary by contribution assumption: employee only about $68,134 at 4% or $45,423 at 6%; with 50% employer match about $45,423 at 4% or $30,282 at 6%; with 100% employer match about $34,067 at 4% or $22,711 at 6%. |
| The Middlesex Corporation Retirement Savings Plan | - | 766 | $14,227,369 | $2,087,627 | $2,725iApproximate average salary by contribution assumption: employee only about $68,134 at 4% or $45,423 at 6%; with 50% employer match about $45,423 at 4% or $30,282 at 6%; with 100% employer match about $34,067 at 4% or $22,711 at 6%. |
| The Middlesex Corporation Health Benefit Plan | - | 540 | - | - | - |
| 2005 | 2 | 524 | $12,262,829 | $1,705,110 | $3,254iApproximate average salary by contribution assumption: employee only about $81,351 at 4% or $54,234 at 6%; with 50% employer match about $54,234 at 4% or $36,156 at 6%; with 100% employer match about $40,675 at 4% or $27,117 at 6%. |
| The Middlesex Corporation Retirement Savings Plan | - | 474 | $12,262,829 | $1,705,110 | $3,597iApproximate average salary by contribution assumption: employee only about $89,932 at 4% or $59,955 at 6%; with 50% employer match about $59,955 at 4% or $39,970 at 6%; with 100% employer match about $44,966 at 4% or $29,977 at 6%. |
| The Middlesex Corporation Health Benefit Plan | - | 524 | - | - | - |
| 2004 | 2 | 473 | $10,674,958 | $1,682,874 | $3,558iApproximate average salary by contribution assumption: employee only about $88,947 at 4% or $59,298 at 6%; with 50% employer match about $59,298 at 4% or $39,532 at 6%; with 100% employer match about $44,473 at 4% or $29,649 at 6%. |
| The Middlesex Corporation Retirement Savings Plan | - | 460 | $10,674,958 | $1,682,874 | $3,658iApproximate average salary by contribution assumption: employee only about $91,461 at 4% or $60,974 at 6%; with 50% employer match about $60,974 at 4% or $40,649 at 6%; with 100% employer match about $45,730 at 4% or $30,487 at 6%. |
| The Middlesex Corporation Health Benefit Plan | - | 473 | - | - | - |
| 2003 | 2 | 462 | $8,897,665 | $1,994,922 | $4,318iApproximate average salary by contribution assumption: employee only about $107,950 at 4% or $71,967 at 6%; with 50% employer match about $71,967 at 4% or $47,978 at 6%; with 100% employer match about $53,975 at 4% or $35,983 at 6%. |
| The Middlesex Corporation Retirement Savings Plan | - | 430 | $8,897,665 | $1,994,922 | $4,639iApproximate average salary by contribution assumption: employee only about $115,984 at 4% or $77,323 at 6%; with 50% employer match about $77,323 at 4% or $51,548 at 6%; with 100% employer match about $57,992 at 4% or $38,661 at 6%. |
| The Middlesex Corporation Health Benefit Plan | - | 462 | - | - | - |
| 2002 | 2 | 334 | $6,170,178 | $1,549,759 | $4,640iApproximate average salary by contribution assumption: employee only about $116,000 at 4% or $77,333 at 6%; with 50% employer match about $77,333 at 4% or $51,556 at 6%; with 100% employer match about $58,000 at 4% or $38,667 at 6%. |
| The Middlesex Corporation Retirement Savings Plan | - | 230 | $6,170,178 | $1,549,759 | $6,738iApproximate average salary by contribution assumption: employee only about $168,452 at 4% or $112,301 at 6%; with 50% employer match about $112,301 at 4% or $74,868 at 6%; with 100% employer match about $84,226 at 4% or $56,151 at 6%. |
| The Middlesex Corporation Health Benefit Plan | - | 334 | - | - | - |
| 2001 | 2 | 417 | $6,566,429 | $1,469,124 | $3,523iApproximate average salary by contribution assumption: employee only about $88,077 at 4% or $58,718 at 6%; with 50% employer match about $58,718 at 4% or $39,145 at 6%; with 100% employer match about $44,038 at 4% or $29,359 at 6%. |
| The Middlesex Corporation Retirement Savings Plan | - | 417 | $6,566,429 | $1,469,124 | $3,523iApproximate average salary by contribution assumption: employee only about $88,077 at 4% or $58,718 at 6%; with 50% employer match about $58,718 at 4% or $39,145 at 6%; with 100% employer match about $44,038 at 4% or $29,359 at 6%. |
| The Middlesex Corporation Health Benefit Plan | - | 307 | - | - | - |
| 2000 | 2 | 396 | $0 | $0 | - |
| The Middlesex Corporation Health Benefit Plan | - | 394 | - | - | - |
| The Middlesex Corporation Retirement Savings Plan | - | 396 | - | - | - |
| 1999 | 1 | 423 | $0 | $0 | - |
| The Middlesex Corporation Health Benefit Plan | - | 423 | - | - | - |