ATI Inc.
US ˙ NYSE ˙ US01741R1023

SecurityATI / ATI Inc.
InstitutionNorthern Trust Corp
Latest Disclosed Ownership1,239,020 shares
Latest Disclosed Value $ 180,227,849
Northern Trust Corp reports 5.53% increase in ownership of ATI / ATI Inc.

On May 14, 2026 - Northern Trust Corp filed a 13F-HR form disclosing ownership of 1,239,020 shares of ATI Inc. (US:ATI) valued at $180,227,849 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 1,174,117 shares of ATI Inc.. This represents a change in shares of 5.53% during the quarter. The current value of the position is $224,386,522 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)
2026-05-14 2026-03-31 13F ATI COM 01741R102 1,239,020 64,903 5.53 180,228 33.76 0.0049
2026-02-17 2025-12-31 13F ATI COM 01741R102 1,174,117 -52,630 -4.29 134,742 35.03 0.0172
2025-11-14 2025-09-30 13F ATI COM 01741R102 1,226,747 -25,970 -2.07 99,784 -7.74 0.0128
2025-08-13 2025-06-30 13F ATI COM 01741R102 1,252,717 -10,044 -0.80 108,160 64.62 0.0149
2025-05-13 2025-03-31 13F ATI COM 01741R102 1,262,761 316,090 33.39 65,701 26.10 0.0098
2025-02-14 2024-12-31 13F ATI COM 01741R102 946,671 270,055 39.91 52,105 15.09 0.0074
2024-11-13 2024-09-30 13F ATI COM 01741R102 676,616 -619,957 -47.82 45,272 -37.03 0.0074
2024-08-14 2024-06-30 13F ATI COM 01741R102 1,296,573 -83,785 -6.07 71,895 1.79 0.0121
2024-05-14 2024-03-31 13F ATI COM 01741R102 1,380,358 -47,286 -3.31 70,633 8.81 0.0122
2024-02-13 2023-12-31 13F ATI COM 01741R102 1,427,644 -13,905 -0.96 64,915 9.43 0.0118
2023-11-13 2023-09-30 13F ATI COM 01741R102 1,441,549 61,582 4.46 59,320 -2.81 0.0115
2023-08-11 2023-06-30 13F ATI COM 01741R102 1,379,967 46,443 3.48 61,036 15.99 0.0117
2023-05-15 2023-03-31 13F ATI COM 01741R102 1,333,524 15,029 1.14 52,621 33.66 0.0104
2023-02-13 2022-12-31 13F ATI COM 01741R102 1,318,495 43,006 3.37 39,370 16.00 0.0083
2022-11-14 2022-09-30 13F ATI COM 01741R102 1,275,489 -1,189 -0.09 33,940 17.06 0.0078
2022-08-12 2022-06-30 13F ALLEGHENY TECHNOLOGIES COM 01741R102 1,276,678 -45,143 -3.42 28,994 -18.28 0.0062
2022-05-13 2022-03-31 13F ALLEGHENY TECHNOLOGIES COM 01741R102 1,321,821 -49,513 -3.61 35,478 62.40 0.0062
2022-02-08 2021-12-31 13F ALLEGHENY TECHNOLOGIES COM 01741R102 1,371,334 -205,775 -13.05 21,846 -16.70 0.0036
2021-11-15 2021-09-30 13F ALLEGHENY TECHNOLOGIES COM 01741R102 1,577,109 -58,605 -3.58 26,227 -23.10 0.0046
2021-08-13 2021-06-30 13F ALLEGHENY TECHNOLOGIES COM 01741R102 1,635,714 -444,482 -21.37 34,104 -22.15 0.0060
2021-05-12 2021-03-31 13F ALLEGHENY TECHNOLOGIES COM 01741R102 2,080,196 -604,742 -22.52 43,809 -2.71 0.0081
2021-02-11 2020-12-31 13F ALLEGHENY TECHNOLOGIES COM 01741R102 2,684,938 -415,287 -13.40 45,027 66.56 0.0088
2020-11-16 2020-09-30 13F ALLEGHENY TECHNOLOGIES COM 01741R102 3,100,225 -426,190 -12.09 27,034 -24.77 0.0059
2020-08-14 2020-06-30 13F ALLEGHENY TECHNOLOGIES COM 01741R102 3,526,415 -262,148 -6.92 35,934 11.59 0.0085
2020-05-14 2020-03-31 13F ALLEGHENY TECHNOLOGIES COM 01741R102 3,788,563 48,981 1.31 32,203 -58.32 0.0092
2020-02-14 2019-12-31 13F ALLEGHENY TECHNOLOGIES COM 01741R102 3,739,582 -13,264 -0.35 77,260 1.66 0.0173
2019-11-13 2019-09-30 13F ALLEGHENY TECHNOLOGIES COM 01741R102 3,752,846 721,798 23.81 75,995 -0.51 0.0182
2019-08-13 2019-06-30 13F ALLEGHENY TECHNOLOGIES COM 01741R102 3,031,048 775,079 34.36 76,382 32.41 0.0181
2019-05-13 2019-03-31 13F ALLEGHENY TECHNOLOGIES COM 01741R102 2,255,969 20,085 0.90 57,685 18.51 0.0142
2019-02-12 2018-12-31 13F ALLEGHENY TECHNOLOGIES COM 01741R102 2,235,884 5,389 0.24 48,674 -26.15 0.0137
2018-11-14 2018-09-30 13F ALLEGHENY TECHNOLOGIES COM 01741R102 2,230,495 -17,529 -0.78 65,912 16.72 0.0161
2018-09-18 2018-06-30 13F/A-1 ALLEGHENY TECHNOLOGIES COM 01741R102 2,248,024 -23,031 -1.01 56,471 5.01 0.0143
2018-08-14 2018-06-30 13F ALLEGHENY TECHNOLOGIES COM 01741R102 2,256,250 -14,805 56,678
2018-05-09 2018-03-31 13F ALLEGHENY TECHNOLOGIES COM 01741R102 2,271,055 -3,699 -0.16 53,779 -2.06 0.0140
2018-02-14 2017-12-31 13F ALLEGHENY TECHNOLOGIES COM 01741R102 2,274,754 173,022 8.23 54,912 9.32 0.0139
2017-11-13 2017-09-30 13F ALLEGHENY TECHNOLOGIES COM 01741R102 2,101,732 62,421 3.06 50,232 44.80 0.0131
2017-08-11 2017-06-30 13F ALLEGHENY TECHNOLOGIES COM 01741R102 2,039,311 25,526 1.27 34,690 -4.08 0.0097
2017-05-12 2017-03-31 13F ALLEGHENY TECHNOLOGIES COM 01741R102 2,013,785 35,844 1.81 36,167 14.78 0.0104
2017-02-13 2016-12-31 13F ALLEGHENY TECHNOLOGIES COM 01741R102 1,977,941 -176,644 -8.20 31,509 -19.07 0.0097
2016-11-09 2016-09-30 13F ALLEGHENY TECHNOLOGIES COM 01741R102 2,154,585 32,092 1.51 38,933 43.86 0.0121
2016-08-12 2016-06-30 13F ALLEGHENY TECHNOLOGIES COM 01741R102 2,122,493 735,663 53.05 27,063 24.17 0.0088
2016-08-19 2016-03-31 13F/A-1 ALLEGHENY TECHNOLOGIES COM 01741R102 1,386,830 9,290 0.67 21,795 40.64 0.0072
2016-05-13 2016-03-31 13F Allegheny Technologi COMM 01741R102 1,386,824 22,606
2016-02-12 2015-12-31 13F Allegheny Technologi COMM 01741R102 1,377,540 33,367 2.48 15,497 -18.70 0.0051
2015-11-12 2015-09-30 13F ALLEGHENY TECHNOLOGIES COM 01741R102 1,344,173 330,851 32.65 19,061 -37.71 0.0064
2015-08-13 2015-06-30 13F ALLEGHENY TECHNOLOGIES COM 01741R102 1,013,322 -542,683 -34.88 30,602 -34.46 0.0207
2015-08-13 2015-06-30 13F Allegheny Technologi COMM 001741R10 379,813 -1,176,192 11,470 0.0078
2015-05-14 2015-03-31 13F Allegheny Technologi COMM 01741R102 1,556,005 -26,193 -1.66 46,695 -15.12 0.0140
2015-02-12 2014-12-31 13F Allegheny Technologi COM 01741R102 1,582,198 -81,598 -4.90 55,012 -10.88 0.0166
2014-11-13 2014-09-30 13F Allegheny Technologi COMM 01741R102 1,663,796 356,256 27.25 61,726 4.67 0.0194
2014-08-14 2014-06-30 13F ALLEGHENY TECHNOLOGIES com 01741R102 1,307,540 -346,847 -20.97 58,971 -5.40 0.0184
2014-05-14 2014-03-31 13F ALLEGHENY TECHNOLOGIES COMM 01741R102 1,654,387 405,126 32.43 62,336 40.05 0.0196
2014-02-21 2013-12-31 13F/A-1 ALLEGHENY TECHNOLOGIES COM 01741R102 1,249,261 -14,561 -1.15 44,511 15.40 0.0143
2014-02-12 2013-12-31 13F ALLEGHENY TECHNOLOGIES COM 01741R102 1,249,261 44,511
2013-11-13 2013-09-30 13F ALLEGHENY TECHNOLOGIES COM 01741R102 1,263,822 -46,841 -3.57 38,572 11.85 0.0136
2013-08-09 2013-06-30 13F ALLEGHENY TECHNOLOGIES COM 01741R102 1,310,663 1,310,663 34,484 0.0125
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.