Amphastar Pharmaceuticals, Inc.
US ˙ NasdaqGS ˙ US03209R1032

SecurityAMPH / Amphastar Pharmaceuticals, Inc.
InstitutionComerica Bank
Latest Disclosed Ownership8,488 shares
Latest Disclosed Value $ 227,308
Comerica Bank reports 10.32% decrease in ownership of AMPH / Amphastar Pharmaceuticals, Inc.

On January 29, 2026 - Comerica Bank filed a 13F-HR form disclosing ownership of 8,488 shares of Amphastar Pharmaceuticals, Inc. (US:AMPH) valued at $227,309 USD as of December 31, 2025. The entity filed a previous 13F-HR on November 14, 2025 disclosing 9,465 shares of Amphastar Pharmaceuticals, Inc.. This represents a change in shares of -10.32% during the quarter. The current value of the position is $158,726 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.

Upgrade to unlock premium data and export to Excel .

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)
2026-01-29 2025-12-31 13F AMPHASTAR PHARMACEUTICALS IN COM 03209R103 8,488 -977 -10.32 227 -9.92 0.0009
2025-11-14 2025-09-30 13F AMPHASTAR PHARMACEUTICALS IN COM 03209R103 9,465 -2,088 -18.07 252 -4.91 0.0009
2025-08-14 2025-06-30 13F AMPHASTAR PHARMACEUTICALS IN COM 03209R103 11,553 -10 -0.09 265 -20.90 0.0010
2025-05-14 2025-03-31 13F AMPHASTAR PHARMACEUTICALS IN COM 03209R103 11,563 -242 -2.05 335 -23.52 0.0014
2025-02-14 2024-12-31 13F/A-1 AMPHASTAR PHARMACEUTICALS IN COM 03209R103 11,805 -1,101 -8.53 438 -30.03 0.0018
2025-02-14 2024-12-31 13F AMPHASTAR PHARMACEUTICALS IN COM 03209R103 11,805 -1,101 438 0.0015
2024-11-14 2024-09-30 13F AMPHASTAR PHARMACEUTICALS IN COM 03209R103 12,906 -487 -3.64 626 17.01 0.0025
2024-08-15 2024-06-30 13F AMPHASTAR PHARMACEUTICALS INC DE COMMON 03209R103 13,393 -2,198 -14.10 536 -21.78 0.0022
2024-05-16 2024-03-31 13F AMPHASTAR PHARMACEUTICALS COMMON 03209R103 15,591 -1,179 -7.03 685 -34.04 0.0030
2024-02-14 2023-12-31 13F AMPHASTAR PHARMACEUTICALS COMMON 03209R103 16,770 620 3.84 1,037 39.76 0.0048
2023-11-21 2023-09-30 13F AMPHASTAR PHARMACEUTICALS IN COMMON 03209R103 16,150 16,150 743 0.0039
2023-08-22 2023-06-30 13F AMPHASTAR PHARMACEUTICALS INC DE COM 03209R103 0 -20,752 -100.00 0 0.0000
2023-01-26 2022-12-31 13F AMPHASTAR PHARMACEUTICALS INC DE COM 03209R103 20,752 -6,840 -24.79 1 -100.00 0.0047
2022-10-28 2022-09-30 13F AMPHASTAR PHARMACEUTICALS INC DE COM 03209R103 27,592 -2,680 -8.85 852 -23.17 0.0072
2022-08-02 2022-06-30 13F AMPHASTAR PHARMACEUTICALS INC DE COM 03209R103 30,272 90 0.30 1,109 -6.02 0.0091
2022-04-27 2022-03-31 13F AMPHASTAR PHARMACEUTICALS INC DE COM 03209R103 30,182 -4,335 -12.56 1,180 37.21 0.0086
2022-02-18 2021-12-31 13F AMPHASTAR PHARMACEUTICALS INC DE COM 03209R103 34,517 2,590 8.11 860 40.29 0.0063
2021-11-22 2021-09-30 13F AMPHASTAR PHARMACEUTICALS INC DE COM 03209R103 31,927 -723 -2.21 613 0.49 0.0037
2021-08-26 2021-06-30 13F AMPHASTAR PHARMACEUTICALS INC DE COM 03209R103 32,650 -2,779 -7.84 610 -0.65 0.0036
2021-04-28 2021-03-31 13F AMPHASTAR PHARMACEUTICALS INC DE COM 03209R103 35,429 -1,428 -3.87 614 -10.89 0.0037
2021-01-28 2020-12-31 13F AMPHASTAR PHARMACEUTICALS INC DE COM 03209R103 36,857 -11 -0.03 689 -10.29 0.0044
2020-10-30 2020-09-30 13F AMPHASTAR PHARMACEUTICALS INC DE COM 03209R103 36,868 2,335 6.76 768 7.87 0.0056
2020-07-31 2020-06-30 13F AMPHASTAR PHARMACEUTICALS INC DE COM 03209R103 34,533 1,199 3.60 712 27.60 0.0055
2020-05-01 2020-03-31 13F AMPHASTAR PHARMACEUTICALS INC DE COM 03209R103 33,334 606 1.85 558 -11.85 0.0051
2020-02-07 2019-12-31 13F AMPHASTAR PHARMACEUTICALS INC DE COM 03209R103 32,728 -14 -0.04 633 -0.94 0.0048
2019-10-31 2019-09-30 13F AMPHASTAR PHARMACEUTICALS INC DE COM 03209R103 32,742 -413 -1.25 639 -3.77 0.0050
2019-08-02 2019-06-30 13F AMPHASTAR PHARMACEUTICALS INC D E COM 03209R103 33,155 -1,548 -4.46 664 -9.04 0.0053
2019-05-02 2019-03-31 13F AMPHASTAR PHARMACEUTICALS INC DE COM 03209R103 34,703 722 2.12 730 -2.67 0.0059
2019-02-06 2018-12-31 13F AMPHASTAR PHARMACEUTICALS INC DE COM 03209R103 33,981 -139 -0.41 750 20.58 0.0064
2018-11-01 2018-09-30 13F AMPHASTAR PHARMACEUTICALS INC DE COM 03209R103 34,120 -3,943 -10.36 622 -0.48 0.0050
2018-08-01 2018-06-30 13F AMPHASTAR PHARMACEUTICALS INC DE COM 03209R103 38,063 1,035 2.80 625 -13.31 0.0044
2018-05-01 2018-03-31 13F AMPHASTAR PHARMACEUTICALS INC DE COM 03209R103 37,028 492 1.35 721 2.12 0.0052
2018-02-02 2017-12-31 13F AMPHASTAR PHARMACEUTICALS INC DE COM 03209R103 36,536 -954 -2.54 706 3.82 0.0047
2017-11-06 2017-09-30 13F AMPHASTAR PHARMACEUTICALS INC DE COM 03209R103 37,490 -2 -0.01 680 2.26 0.0049
2017-08-03 2017-06-30 13F AMPHASTAR PHARMACEUTICALS INC DE COM 03209R103 37,492 -2,120 -5.35 665 10.83 0.0050
2017-05-03 2017-03-31 13F AMPHASTAR PHARMACEUTICALS INC DE COM 03209R103 39,612 1,570 4.13 600 -7.98 0.0046
2017-02-08 2016-12-31 13F AMPHASTAR PHARMACEUTICALS INC DE COM 03209R103 38,042 2,628 7.42 652 -3.55 0.0052
2016-11-10 2016-09-30 13F AMPHASTAR PHARMACEUTICALS INC DE COM 03209R103 35,414 35,414 676 0.0399
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.