Amkor Technology, Inc.
MX ˙ BMV ˙ US0316521006
SecurityMX:AMKR / Amkor Technology, Inc.
InstitutionRhumbline Advisers
Latest Disclosed Ownership314,616 shares
Latest Disclosed Value $ 14,167,120
Rhumbline Advisers reports 3.78% increase in ownership of AMKR / Amkor Technology, Inc.

On May 12, 2026 - Rhumbline Advisers filed a 13F-HR form disclosing ownership of 314,616 shares of Amkor Technology, Inc. (MX:AMKR) valued at $14,167,120 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 13, 2026 disclosing 303,154 shares of Amkor Technology, Inc.. This represents a change in shares of 3.78% 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 AMKOR TECHNOLOGY INC COM COM 031652100 314,616 11,462 3.78 14,167 18.37 0.0121
2026-02-13 2025-12-31 13F AMKOR TECHNOLOGY INC COM COM 031652100 303,154 -12,702 -4.02 11,968 33.42 0.0097
2025-11-06 2025-09-30 13F AMKOR TECHNOLOGY INC COM COM 031652100 315,856 -6,797 -2.11 8,970 32.46 0.0072
2025-08-12 2025-06-30 13F AMKOR TECHNOLOGY INC COM COM 031652100 322,653 14,901 4.84 6,772 21.86 0.0058
2025-05-29 2025-03-31 13F/A-1 AMKOR TECHNOLOGY INC COM COM 031652100 307,752 -1,391 -0.45 5,558 -30.02 0.0052
2025-04-08 2025-03-31 13F AMKOR TECHNOLOGY INC COM COM 031652100 307,752 -1,391 5,558 0.0052
2025-05-29 2024-12-31 13F/A-1 AMKOR TECHNOLOGY INC COM COM 031652100 309,143 -8,303 -2.62 7,942 -18.24 0.0071
2025-01-30 2024-12-31 13F AMKOR TECHNOLOGY INC COM COM 031652100 309,143 -8,303 7,942 0.0071
2024-11-12 2024-09-30 13F AMKOR TECHNOLOGY INC COM COM 031652100 317,446 16,276 5.40 9,714 -19.41 0.0088
2024-08-01 2024-06-30 13F AMKOR TECHNOLOGY INC COM COM 031652100 301,170 -73,511 -19.62 12,053 -0.22 0.0113
2024-05-09 2024-03-31 13F AMKOR TECHNOLOGY INC COM COM 031652100 374,681 4,496 1.21 12,080 -1.92 0.0116
2024-02-08 2023-12-31 13F AMKOR TECHNOLOGY INC COM COM 031652100 370,185 14,397 4.05 12,316 53.18 0.0129
2023-11-09 2023-09-30 13F AMKOR TECHNOLOGY INC COM COM 031652100 355,788 5,972 1.71 8,041 -22.74 0.0093
2023-08-08 2023-06-30 13F AMKOR TECHNOLOGY INC COM COM 031652100 349,816 662 0.19 10,407 115,533.33 0.0117
2023-05-11 2023-03-31 13F AMKOR TECHNOLOGY INC COM COM 031652100 349,154 0 0.00 9 -99.89 0.0112
2023-02-14 2022-12-31 13F AMKOR TECHNOLOGY INC COM COM 031652100 349,154 2,675 0.77 8,373 41.75 0.0113
2022-11-10 2022-09-30 13F AMKOR TECHNOLOGY INC COM COM 031652100 346,479 12,185 3.64 5,907 4.25 0.0088
2022-08-11 2022-06-30 13F AMKOR TECHNOLOGY INC COM COM 031652100 334,294 27,240 8.87 5,666 -15.04 0.0083
2022-05-12 2022-03-31 13F AMKOR TECHNOLOGY INC COM COM 031652100 307,054 -1,127 -0.37 6,669 -12.71 0.0086
2022-02-10 2021-12-31 13F AMKOR TECHNOLOGY INC COM COM 031652100 308,181 -2,311 -0.74 7,640 -1.38 0.0094
2021-11-12 2021-09-30 13F AMKOR TECHNOLOGY INC COM COM 031652100 310,492 -14,096 -4.34 7,747 0.83 0.0105
2021-08-05 2021-06-30 13F AMKOR TECHNOLOGY INC COM COM 031652100 324,588 -432 -0.13 7,683 -0.30 0.0101
2021-05-06 2021-03-31 13F AMKOR TECHNOLOGY INC COM COM 031652100 325,020 158,701 95.42 7,706 207.26 0.0105
2021-02-10 2020-12-31 13F AMKOR TECHNOLOGY INC COM COM 031652100 166,319 -2,699 -1.60 2,508 32.49 0.0035
2020-11-12 2020-09-30 13F AMKOR TECHNOLOGY INC COM COM 031652100 169,018 -29,630 -14.92 1,893 -22.58 0.0030
2020-08-13 2020-06-30 13F AMKOR TECHNOLOGY INC COM COM 031652100 198,648 3,872 1.99 2,445 61.17 0.0041
2020-05-06 2020-03-31 13F AMKOR TECHNOLOGY INC COM COM 031652100 194,776 18,682 10.61 1,517 -33.73 0.0032
2020-02-05 2019-12-31 13F AMKOR TECHNOLOGY INC COM COM 031652100 176,094 1,445 0.83 2,289 44.05 0.0038
2019-10-23 2019-09-30 13F AMKOR TECHNOLOGY INC COM COM 031652100 174,649 13,774 8.56 1,589 32.42 0.0029
2019-08-14 2019-06-30 13F AMKOR TECHNOLOGY INC COM COM 031652100 160,875 7,718 5.04 1,200 -8.26 0.0023
2019-05-01 2019-03-31 13F AMKOR TECHNOLOGY INC COM COM 031652100 153,157 745 0.49 1,308 30.80 0.0025
2019-01-31 2018-12-31 13F AMKOR TECHNOLOGY INC COM COM 031652100 152,412 43,291 39.67 1,000 24.07 0.0022
2018-11-07 2018-09-30 13F AMKOR TECHNOLOGY INC COM COM 031652100 109,121 160 0.15 806 -13.89 0.0016
2018-08-06 2018-06-30 13F AMKOR TECHNOLOGY INC COM COM 031652100 108,961 1,365 1.27 936 -14.13 0.0019
2018-05-02 2018-03-31 13F AMKOR TECHNOLOGY INC COM COM 031652100 107,596 -2,649 -2.40 1,090 -1.62 0.0023
2018-02-09 2017-12-31 13F AMKOR TECHNOLOGY INC COM COM 031652100 110,245 -18,107 -14.11 1,108 -18.17 0.0023
2017-11-06 2017-09-30 13F AMKOR TECHNOLOGY INC COM COM 031652100 128,352 690 0.54 1,354 8.58 0.0029
2017-08-02 2017-06-30 13F AMKOR TECHNOLOGY INC COM COM 031652100 127,662 1,336 1.06 1,247 -14.82 0.0028
2017-05-02 2017-03-31 13F AMKOR TECHNOLOGY INC COM COM 031652100 126,326 5,566 4.61 1,464 14.91 0.0034
2017-01-27 2016-12-31 13F AMKOR TECHNOLOGY INC COM COM 031652100 120,760 -4,429 -3.54 1,274 4.68 0.0032
2016-11-08 2016-09-30 13F AMKOR TECHNOLOGY INC COM COM 031652100 125,189 1,650 1.34 1,217 71.41 0.0034
2016-08-11 2016-06-30 13F AMKOR TECHNOLOGY INC COM COM 031652100 123,539 -32,681 -20.92 710 -22.83 0.0021
2016-05-02 2016-03-31 13F AMKOR TECHNOLOGY INC COMMON ST COM 031652100 156,220 17,075 12.27 920 8.75 0.0029
2016-02-03 2015-12-31 13F AMKOR TECHNOLOGY INC COMMON ST COM 031652100 139,145 4,970 3.70 846 40.53 0.0027
2015-11-04 2015-09-30 13F AMKOR TECHNOLOGY INC COMMON ST COM 031652100 134,175 7,031 5.53 602 -20.79 0.0020
2015-08-04 2015-06-30 13F AMKOR TECHNOLOGY INC COMMON ST COM 031652100 127,144 25,635 25.25 760 -15.27 0.0024
2015-05-12 2015-03-31 13F AMKOR TECHNOLOGY INC COMMON ST COM 031652100 101,509 3,510 3.58 897 28.88 0.0026
2015-02-06 2014-12-31 13F AMKOR TECHNOLOGY INC COMMON ST COM 031652100 97,999 5,310 5.73 696 -10.77 0.0020
2014-11-12 2014-09-30 13F AMKOR TECHNOLOGY INC COMMON ST COM 031652100 92,689 -170 -0.18 780 -24.86 0.0023
2014-08-06 2014-06-30 13F AMKOR TECHNOLOGY INC COMMON ST COM 031652100 92,859 -365 -0.39 1,038 62.19 0.0030
2014-05-06 2014-03-31 13F AMKOR TECHNOLOGY INC COMMON ST COM 031652100 93,224 -2,830 -2.95 640 8.66 0.0019
2014-02-03 2013-12-31 13F AMKOR TECHNOLOGY INC COMMON ST COM 031652100 96,054 -6,400 -6.25 589 33.86 0.0017
2013-11-05 2013-09-30 13F AMKOR TECHNOLOGY INC COMMON ST COM 031652100 102,454 5,112 5.25 440 7.32 0.0014
2013-08-07 2013-06-30 13F AMKOR TECHNOLOGY INC COMMON ST COM 031652100 97,342 97,342 410 0.0013
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.