ATI Inc.
US ˙ NYSE ˙ US01741R1023

SecurityATI / ATI Inc.
InstitutionSei Investments Co
Latest Disclosed Ownership119,585 shares
Latest Disclosed Value $ 13,723,585
Sei Investments Co ownership in ATI / ATI Inc.

On February 13, 2026 - Sei Investments Co filed a 13F-HR form disclosing ownership of 119,585 shares of ATI Inc. (US:ATI) valued at $13,723,575 USD as of December 31, 2025. The entity filed a previous 13F-HR on November 13, 2025 disclosing 117,497 shares of ATI Inc.. This represents a change in shares of 1.78% during the quarter. The current value of the position is $21,656,844 USD.

Sei Investments Co has a history of taking positions in derivatives of the underlying security (ATI) in the form of stock options.

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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Institutional Put/Call Ratios
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In addition to reporting standard equity and debt issues, institutions with more than 100MM assets under management must also disclose their put and call option holdings. Since put options generally indicate negative sentiment, and call options indicate positive sentiment, we can get a sense of the overall institutional sentiment by plotting the ratio of puts to calls. The chart to the right plots the historical put/call ratio for this instrument.

Using Put/Call Ratio as an indicator of investor sentiment overcomes one of the key deficiencies of using total institutional ownership, which is that a significant amount of assets under management are invested passively to track indices. Passively-managed funds do not typically buy options, so the put/call ratio indicator more closely tracks the sentiment of actively-managed funds.

ATI / ATI Inc. Historical Put/Call Ratio
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 ATI COM 01741R102 119,585 2,088 1.78 13,724 43.59 0.0135
2025-11-13 2025-09-30 13F ATI COM 01741R102 117,497 -5,669 -4.60 9,557 -10.13 0.0103
2025-08-14 2025-06-30 13F ATI COM 01741R102 123,166 -24,857 -16.79 10,634 38.09 0.0123
2025-05-14 2025-03-31 13F/A-1 ATI COM 01741R102 148,023 -22,943 -13.42 7,702 -18.15 0.0099
2025-05-13 2025-03-31 13F ATI COM 01741R102 173,605 2,639 9,547 0.0104
2025-02-11 2024-12-31 13F ATI COM 01741R102 170,966 -76,667 -30.96 9,410 -43.21 0.0121
2024-11-12 2024-09-30 13F ATI COM 01741R102 247,633 -38,514 -13.46 16,569 4.43 0.0215
2024-08-13 2024-06-30 13F ATI COM 01741R102 286,147 -7,215 -2.46 15,867 5.70 0.0225
2024-05-07 2024-03-31 13F ATI COM 01741R102 293,362 -37,952 -11.45 15,011 -0.35 0.0220
2024-02-14 2023-12-31 13F ATI COM 01741R102 331,314 -62,735 -15.92 15,065 -7.10 0.0242
2023-11-14 2023-09-30 13F ATI COM 01741R102 394,049 126,626 47.35 16,215 37.09 0.0291
2023-08-11 2023-06-30 13F ATI COM 01741R102 267,423 23,101 9.46 11,828 22.70 0.0206
2023-05-12 2023-03-31 13F ATI COM 01741R102 244,322 217,786 820.72 9,641 1,117.17 0.0179
2023-02-10 2022-12-31 13F ATI COM 01741R102 26,536 -27,081 -50.51 792 -44.50 0.0018
2022-11-14 2022-09-30 13F ATI COM 01741R102 53,617 -6,110 -10.23 1,427 5.24 0.0032
2022-08-15 2022-06-30 13F ALLEGHENY TECHNOLOGIES COM 01741R102 59,727 2,745 4.82 1,356 -11.31 0.0029
2022-05-13 2022-03-31 13F ALLEGHENY TECHNOLOGIES COM 01741R102 56,982 44,270 348.25 1,529 653.20 0.0031
2022-02-14 2021-12-31 13F ALLEGHENY TECHNOLOGIES COM 01741R102 12,712 -73,963 -85.33 203 -85.91 0.0004
2021-11-12 2021-09-30 13F ALLEGHENY TECHNOLOGIES COM 01741R102 86,675 12,258 16.47 1,441 -7.15 0.0030
2021-08-06 2021-06-30 13F ALLEGHENY TECHNOLOGIES COM 01741R102 74,417 -8,133 -9.85 1,552 -10.75 0.0034
2021-05-12 2021-03-31 13F ALLEGHENY TECHNOLOGIES COM 01741R102 82,550 -13,017 -13.62 1,739 8.48 0.0044
2021-02-08 2020-12-31 13F ALLEGHENY TECHNOLOGIES COM 01741R102 95,567 80,594 538.26 1,603 1,123.66 0.0041
2020-12-04 2020-09-30 13F/A-1 ALLEGHENY TECHNOLOGIES COM 01741R102 14,973 2,855 23.56 131 6.50 0.0004
2020-11-06 2020-09-30 13F ALLEGHENY TECHNOLOGIES COM 01741R102 14,973 2,855 131 315.4189
2020-08-17 2020-06-30 13F/A-1 ALLEGHENY TECHNOLOGIES COM 01741R102 12,118 -232,284 -95.04 123 -94.08 0.0004
2020-08-11 2020-06-30 13F ALLEGHENY TECHNOLOGIES COM 01741R102 298,091 53,689 6,159 16,706.6153
2020-05-14 2020-03-31 13F ALLEGHENY TECHNOLOGIES COM 01741R102 244,402 -61,527 -20.11 2,078 -67.25 0.0076
2020-02-06 2019-12-31 13F ALLEGHENY TECHNOLOGIES COM 01741R102 305,929 -37,440 -10.90 6,346 -8.94 0.0189
2019-11-12 2019-09-30 13F ALLEGHENY TECHNOLOGIES COM 01741R102 343,369 -101,294 -22.78 6,969 -37.94 0.0178
2019-08-14 2019-06-30 13F ALLEGHENY TECHNOLOGIES COM 01741R102 444,663 89,321 25.14 11,229 23.31 0.0367
2019-05-15 2019-03-31 13F ALLEGHENY TECHNOLOGIES COM 01741R102 355,342 234,956 195.17 9,106 158.55 0.0306
2019-02-13 2018-12-31 13F ALLEGHENY TECHNOLOGIES COM 01741R102 120,386 -124,254 -50.79 3,522 -51.30 0.0125
2018-11-08 2018-09-30 13F ALLEGHENY TECHNOLOGIES COM 01741R102 244,640 -242,873 -49.82 7,232 -40.94 0.0262
2018-08-03 2018-06-30 13F ALLEGHENY TECHNOLOGIES COM 01741R102 487,513 -61,767 -11.25 12,246 -5.85 0.0416
2018-05-11 2018-03-31 13F ALLEGHENY TECHNOLOGIES COM 01741R102 549,280 -33,676 -5.78 13,007 -7.57 0.0499
2018-02-08 2017-12-31 13F ALLEGHENY TECHNOLOGIES COM 01741R102 582,956 22,968 4.10 14,073 5.14 0.0489
2017-11-06 2017-09-30 13F ALLEGHENY TECHNOLOGIES COM 01741R102 559,988 114,705 25.76 13,385 76.72 0.0476
2017-07-31 2017-06-30 13F ALLEGHENY TECHNOLOGIES COM 01741R102 445,283 70,764 18.89 7,574 12.61 0.0302
2017-05-05 2017-03-31 13F ALLEGHENY TECHNOLOGIES COM 01741R102 374,519 169,767 82.91 6,726 106.19 0.0295
2017-02-02 2016-12-31 13F ALLEGHENY TECHNOLOGIES COM 01741R102 204,752 3,087 1.53 3,262 -10.46 0.0158
2016-11-04 2016-09-30 13F ALLEGHENY TECHNOLOGIES COM 01741R102 201,665 465 0.23 3,643 42.03 0.0185
2016-08-11 2016-06-30 13F ALLEGHENY TECHNOLOGIES COM 01741R102 201,200 151,348 303.59 2,565 215.50 0.0154
2016-05-10 2016-03-31 13F/A-1 ALLEGHENY TECHNOLOGIES COM 01741R102 49,852 40,375 426.03 813 659.81 0.0051
2016-02-03 2015-12-31 13F ALLEGHENY TECHNOLOGIES COM 01741R102 9,477 1,015 11.99 107 -10.83 0.0007
2015-11-02 2015-09-30 13F/A-1 ALLEGHENY TECHNOLOGIES COM 01741R102 8,462 -12 -0.14 120 -53.31 0.0011
2015-10-30 2015-09-30 13F ALLEGHENY TECHNOLOGIES COM 01741R102 8,462 121
2015-08-07 2015-06-30 13F/A-1 ALLEGHENY TECHNOLOGIES COM 01741R102 8,474 -4,360 -33.97 257 -33.25 0.0023
2015-08-04 2015-06-30 13F ALLEGHENY TECHNOLOGIES COM 01741R102 8,474 -4,360 257 0.0023
2015-05-14 2015-03-31 13F/A-1 ALLEGHENY TECHNOLOGIES COM 01741R102 12,834 -16,546 -56.32 385 -62.37 0.0033
2015-05-01 2015-03-31 13F ALLEGHANY CORP DEL PUT 01741R102 12,834 12,834 385 0.0033
2015-02-10 2014-12-31 13F ALLEGHENY TECHNOLOGIES COM 01741R102 29,380 29,380 1,023 0.0090
Disclosed Put Options
File
Date
Effective
Date
Form Security Class ID Opt Avg Share Price Shares ΔShares
(%)
Value
(x1000)
ΔValue
(%)
Prior Allocation
(%)
Allocation
(%)
ΔAllocation
(%)
Cost Basis
(x1000)
Profit
(x1000)
Return
(%)
2015-05-01 2015-03-31 13F ALLEGHANY CORP DEL PUT 12,834 385 n/a n/a n/a
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.