ATI Inc.
MX ˙ BMV ˙ US01741R1023
SecurityMX:ATI / ATI Inc.
InstitutionRhumbline Advisers
Latest Disclosed Ownership354,371 shares
Latest Disclosed Value $ 51,546,744
Rhumbline Advisers reports 1.96% increase in ownership of ATI / ATI Inc.

On May 12, 2026 - Rhumbline Advisers filed a 13F-HR form disclosing ownership of 354,371 shares of ATI Inc. (MX:ATI) valued at $51,546,744 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 13, 2026 disclosing 347,548 shares of ATI Inc.. This represents a change in shares of 1.96% during the quarter.

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)
2026-05-12 2026-03-31 13F ATI COM 01741R102 354,371 6,823 1.96 51,547 29.24 0.0441
2026-02-13 2025-12-31 13F ATI COM 01741R102 347,548 -14,670 -4.05 39,885 35.37 0.0322
2025-11-06 2025-09-30 13F ATI COM 01741R102 362,218 -7,794 -2.11 29,463 -7.78 0.0237
2025-08-12 2025-06-30 13F ATI COM 01741R102 370,012 7,480 2.06 31,947 69.37 0.0274
2025-05-29 2025-03-31 13F/A-1 ATI COM 01741R102 362,532 58,241 19.14 18,862 12.62 0.0176
2025-04-08 2025-03-31 13F ATI COM 01741R102 362,532 58,241 18,862 0.0176
2025-05-29 2024-12-31 13F/A-1 ATI COM 01741R102 304,291 16,975 5.91 16,748 -12.88 0.0150
2025-01-30 2024-12-31 13F ATI COM 01741R102 304,291 16,975 16,748 0.0150
2024-11-12 2024-09-30 13F ATI COM 01741R102 287,316 -9,538 -3.21 19,224 16.79 0.0173
2024-08-01 2024-06-30 13F ATI COM 01741R102 296,854 -70,614 -19.22 16,461 -12.46 0.0155
2024-05-09 2024-03-31 13F ATI COM 01741R102 367,468 -4,384 -1.18 18,803 11.21 0.0181
2024-02-08 2023-12-31 13F ATI COM 01741R102 371,852 -16,249 -4.19 16,908 5.87 0.0177
2023-11-09 2023-09-30 13F ATI COM 01741R102 388,101 3,221 0.84 15,970 -6.19 0.0185
2023-08-08 2023-06-30 13F ATI COM 01741R102 384,880 -7,447 -1.90 17,023 113,386.67 0.0191
2023-05-11 2023-03-31 13F ATI COM 01741R102 392,327 16,841 4.49 15 -99.87 0.0191
2023-02-14 2022-12-31 13F ATI COM 01741R102 375,486 6,823 1.85 11,212 14.29 0.0151
2022-11-10 2022-09-30 13F ATI COM 01741R102 368,663 23,997 6.96 9,810 25.34 0.0146
2022-08-11 2022-06-30 13F ALLEGHENY TECHNOLOGIES INC COM COM 01741R102 344,666 -3,318 -0.95 7,827 -16.20 0.0114
2022-05-12 2022-03-31 13F ALLEGHENY TECHNOLOGIES INC COM COM 01741R102 347,984 14,825 4.45 9,340 75.99 0.0120
2022-02-10 2021-12-31 13F ALLEGHENY TECHNOLOGIES INC COM COM 01741R102 333,159 -8,974 -2.62 5,307 -6.73 0.0065
2021-11-12 2021-09-30 13F ALLEGHENY TECHNOLOGIES INC COM COM 01741R102 342,133 -50,580 -12.88 5,690 -30.51 0.0077
2021-08-05 2021-06-30 13F ALLEGHENY TECHNOLOGIES INC COM COM 01741R102 392,713 -44,279 -10.13 8,188 -11.03 0.0107
2021-05-06 2021-03-31 13F ALLEGHENY TECHNOLOGIES INC COM COM 01741R102 436,992 -2,823 -0.64 9,203 24.77 0.0125
2021-02-10 2020-12-31 13F ALLEGHENY TECHNOLOGIES INC COM COM 01741R102 439,815 40,054 10.02 7,376 111.59 0.0102
2020-11-12 2020-09-30 13F ALLEGHENY TECHNOLOGIES INC COM COM 01741R102 399,761 -70,342 -14.96 3,486 -27.22 0.0055
2020-08-13 2020-06-30 13F ALLEGHENY TECHNOLOGIES INC COM COM 01741R102 470,103 12,356 2.70 4,790 23.10 0.0080
2020-05-06 2020-03-31 13F ALLEGHENY TECHNOLOGIES INC COM COM 01741R102 457,747 24,839 5.74 3,891 -56.50 0.0082
2020-02-05 2019-12-31 13F ALLEGHENY TECHNOLOGIES INC COM COM 01741R102 432,908 1,772 0.41 8,944 2.44 0.0150
2019-10-23 2019-09-30 13F ALLEGHENY TECHNOLOGIES INC COM COM 01741R102 431,136 648 0.15 8,731 -19.52 0.0160
2019-08-14 2019-06-30 13F ALLEGHENY TECHNOLOGIES INC COM COM 01741R102 430,488 8,268 1.96 10,848 0.48 0.0204
2019-05-01 2019-03-31 13F ALLEGHENY TECHNOLOGIES INC COM COM 01741R102 422,220 6,824 1.64 10,796 19.39 0.0209
2019-01-31 2018-12-31 13F ALLEGHENY TECHNOLOGIES INC COM COM 01741R102 415,396 171,303 70.18 9,043 25.37 0.0197
2018-11-07 2018-09-30 13F ALLEGHENY TECHNOLOGIES INC COM COM 01741R102 244,093 1,267 0.52 7,213 18.25 0.0139
2018-08-06 2018-06-30 13F ALLEGHENY TECHNOLOGIES INC COM COM 01741R102 242,826 3,143 1.31 6,100 7.47 0.0123
2018-05-02 2018-03-31 13F ALLEGHENY TECHNOLOGIES INC COM COM 01741R102 239,683 -9,898 -3.97 5,676 -5.79 0.0119
2018-02-09 2017-12-31 13F ALLEGHENY TECHNOLOGIES INC COM COM 01741R102 249,581 9,942 4.15 6,025 5.20 0.0122
2017-11-06 2017-09-30 13F ALLEGHENY TECHNOLOGIES INC COM COM 01741R102 239,639 9,991 4.35 5,727 46.62 0.0125
2017-08-02 2017-06-30 13F ALLEGHENY TECHNOLOGIES INC COM COM 01741R102 229,648 -4,964 -2.12 3,906 -7.31 0.0089
2017-05-02 2017-03-31 13F ALLEGHENY TECHNOLOGIES INC COM COM 01741R102 234,612 6,268 2.74 4,214 15.83 0.0098
2017-01-27 2016-12-31 13F ALLEGHENY TECHNOLOGIES INC COM COM 01741R102 228,344 -1,383 -0.60 3,638 -12.36 0.0092
2016-11-08 2016-09-30 13F ALLEGHENY TECHNOLOGIES INC COM COM 01741R102 229,727 9,430 4.28 4,151 47.78 0.0114
2016-08-11 2016-06-30 13F ALLEGHENY TECHNOLOGIES INC COM COM 01741R102 220,297 55,633 33.79 2,809 4.66 0.0083
2016-05-02 2016-03-31 13F ALLEGHENY TECHNOLOGIES INC COM COM 01741R102 164,664 4,510 2.82 2,684 48.95 0.0083
2016-02-03 2015-12-31 13F ALLEGHENY TECHNOLOGIES INC COM COM 01741R102 160,154 684 0.43 1,802 -20.30 0.0058
2015-11-04 2015-09-30 13F ALLEGHENY TECHNOLOGIES INC COM COM 01741R102 159,470 5,037 3.26 2,261 -51.52 0.0077
2015-08-04 2015-06-30 13F ALLEGHENY TECHNOLOGIES INC COM COM 01741R102 154,433 16,085 11.63 4,664 12.33 0.0149
2015-05-12 2015-03-31 13F ALLEGHENY TECHNOLOGIES INC COM COM 01741R102 138,348 -1,060 -0.76 4,152 -14.34 0.0120
2015-02-06 2014-12-31 13F ALLEGHENY TECHNOLOGIES INC COM COM 01741R102 139,408 1,029 0.74 4,847 -5.59 0.0141
2014-11-12 2014-09-30 13F ALLEGHENY TECHNOLOGIES INC COM COM 01741R102 138,379 -497 -0.36 5,134 -18.03 0.0154
2014-08-06 2014-06-30 13F ALLEGHENY TECHNOLOGIES INC COM COM 01741R102 138,876 -6,629 -4.56 6,263 14.23 0.0184
2014-05-06 2014-03-31 13F ALLEGHENY TECHNOLOGIES INC COM COM 01741R102 145,505 -3,870 -2.59 5,483 3.03 0.0163
2014-02-03 2013-12-31 13F ALLEGHENY TECHNOLOGIES INC COM COM 01741R102 149,375 -17,899 -10.70 5,322 4.25 0.0157
2013-11-05 2013-09-30 13F ALLEGHENY TECHNOLOGIES INC COM COM 01741R102 167,274 864 0.52 5,105 16.61 0.0158
2013-08-07 2013-06-30 13F ALLEGHENY TECHNOLOGIES INC COM COM 01741R102 166,410 166,410 4,378 0.0141
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.