AdvanSix Inc.
US ˙ NYSE ˙ US00773T1016

SecurityASIX / AdvanSix Inc.
InstitutionSei Investments Co
Latest Disclosed Ownership37,861 shares
Latest Disclosed Value $ 654,998
Sei Investments Co ownership in ASIX / AdvanSix Inc.

On February 13, 2026 - Sei Investments Co filed a 13F-HR form disclosing ownership of 37,861 shares of AdvanSix Inc. (US:ASIX) valued at $654,995 USD as of December 31, 2025. The entity filed a previous 13F-HR on November 13, 2025 disclosing 0 shares of AdvanSix Inc.. The current value of the position is $839,000 USD.

Institutional Ownership: 13F and NPORT Filings

The Security and Class in the table below are shown exactly as filed by the investor. We do our best to track continuity of investments through acquisitions, and this will be reflected in the table as changes in names. In addition to descriptive data, performance of the investment is shown over time. To calculate quarterly performance, we first calculate cost basis of the shares purchased during the quarter, then use that to calculate gross profit. Quarterly return is Gross Profit / Starting Portfolio value.

Note that cost basis is calculated and stored in thousands, so small quarterly changes in shares frequently result in a cost basis of zero.

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Disclosed Equity Positions (from 13F/NPORT Filings)
File
Date		 Effective
Date		Form Security Class ID Avg Price
Paid (Est)		 Reported
Shares		 ΔShares ΔShares
(%)		 Reported
Value
(x1000)		 ΔValue
(%)		 Alloc
(%)		 ΔAlloc ΔAlloc (%) Cost Basis
(x1000)		 Unrealized
Gain/Loss
(x1000)
2026-02-13 2025-12-31 13F ADVANSIX COM 00773T101 37,861 37,861 655 0.0006
2025-11-13 2025-09-30 13F ADVANSIX COM 00773T101 0 -13,156 -100.00 0 -100.00
2025-08-14 2025-06-30 13F ADVANSIX COM 00773T101 13,156 -247 -1.84 313 2.97 0.0004
2025-05-14 2025-03-31 13F/A-1 ADVANSIX COM 00773T101 13,403 -2,535 -15.91 304 -33.11 0.0004
2025-05-13 2025-03-31 13F ADVANSIX COM 00773T101 15,303 -635 403 0.0004
2025-02-11 2024-12-31 13F ADVANSIX COM 00773T101 15,938 6,087 61.79 454 51.51 0.0006
2024-11-12 2024-09-30 13F ADVANSIX COM 00773T101 9,851 -3,199 -24.51 299 0.00 0.0004
2024-08-13 2024-06-30 13F ADVANSIX COM 00773T101 13,050 200 1.56 299 -18.53 0.0004
2024-05-07 2024-03-31 13F ADVANSIX COM 00773T101 12,850 -56,439 -81.45 368 -82.31 0.0005
2024-02-14 2023-12-31 13F ADVANSIX COM 00773T101 69,289 -21,922 -24.03 2,076 -26.78 0.0033
2023-11-14 2023-09-30 13F ADVANSIX COM 00773T101 91,211 -45,283 -33.18 2,835 -40.64 0.0051
2023-08-11 2023-06-30 13F ADVANSIX COM 00773T101 136,494 -64 -0.05 4,775 -8.65 0.0083
2023-05-12 2023-03-31 13F ADVANSIX COM 00773T101 136,558 -22,772 -14.29 5,226 -13.72 0.0097
2023-02-10 2022-12-31 13F ADVANSIX COM 00773T101 159,330 -14,452 -8.32 6,058 8.59 0.0135
2022-11-14 2022-09-30 13F ADVANSIX COM 00773T101 173,782 14,931 9.40 5,578 5.03 0.0124
2022-08-15 2022-06-30 13F ADVANSIX COM 00773T101 158,851 -22,027 -12.18 5,311 -42.53 0.0115
2022-05-13 2022-03-31 13F ADVANSIX COM 00773T101 180,878 48,763 36.91 9,241 48.31 0.0186
2022-02-14 2021-12-31 13F ADVANSIX COM 00773T101 132,115 19,659 17.48 6,231 39.40 0.0117
2021-11-12 2021-09-30 13F ADVANSIX COM 00773T101 112,456 19,337 20.77 4,470 60.79 0.0094
2021-08-06 2021-06-30 13F ADVANSIX COM 00773T101 93,119 5,251 5.98 2,780 17.95 0.0062
2021-05-12 2021-03-31 13F ADVANSIX COM 00773T101 87,868 22,234 33.88 2,357 79.65 0.0059
2021-02-08 2020-12-31 13F ADVANSIX COM 00773T101 65,634 -7,284 -9.99 1,312 39.72 0.0034
2020-12-04 2020-09-30 13F/A-1 ADVANSIX COM 00773T101 72,918 72,918 939 0.0027
2020-11-06 2020-09-30 13F ADVANSIX COM 00773T101 72,941 72,941 939 2,260.9032
2019-08-14 2019-06-30 13F ADVANSIX COM 00773T101 0 -8,063 -100.00 0 -100.00
2019-05-15 2019-03-31 13F ADVANSIX COM 00773T101 8,063 -455 -5.34 230 4.55 0.0008
2019-02-13 2018-12-31 13F ADVANSIX COM 00773T101 8,518 7,363 637.49 220 436.59 0.0008
2018-11-08 2018-09-30 13F ADVANSIX COM 00773T101 1,155 -3,167 -73.28 41 -74.21 0.0001
2018-08-03 2018-06-30 13F ADVANSIX COM 00773T101 4,322 -95 -2.15 159 3.92 0.0005
2018-05-11 2018-03-31 13F ADVANSIX COM 00773T101 4,417 -4,611 -51.07 153 -59.63 0.0006
2018-02-08 2017-12-31 13F ADVANSIX COM 00773T101 9,028 -10,405 -53.54 379 -50.91 0.0013
2017-11-06 2017-09-30 13F ADVANSIX COM 00773T101 19,433 3,597 22.71 772 56.28 0.0027
2017-07-31 2017-06-30 13F ADVANSIX COM 00773T101 15,836 6,490 69.44 494 93.73 0.0020
2017-05-05 2017-03-31 13F ADVANSIX COM 00773T101 9,346 6,244 201.29 255 275.00 0.0011
2017-02-02 2016-12-31 13F ADVANSIX COM 00773T101 3,102 3,102 68 0.0003
Legend
Shares
The total number of shares held by the institution at the end of the reporting period (the effective date). This is provided in the filing.
Value
The total value of the shares as of the effective date. This is provided in the filing.
Avg. Share Price
The weighted average share price of the shares held by the institution. We use FIFO accounting to determine this price
Class
This is the security class as indicated by the filer. There are a variety of values for this field. Common values include "EC" = equity common, "EP" - equity preferred
Allocation (%)
The percent of the institution's portfolio that this position represents. This is provided in NPORT filings. For 13F filings, we calculate it.
Change in Allocation
The change in allocation from the prior reporting period. This is calculated as current allocation - prior allocation.
Change in Allocation (%)
The percent change in allocation from the prior reporting period. This is calculated as (current allocation - prior allocation) / prior allocation.
Cost Basis
The total cost of the shares held. This is calculated as reported shares * avg. share price
Unrealized Gain/Loss
This is the market value of the position as of the effective date minus the cost basis.