Westamerica Bancorporation
US ˙ NasdaqGS ˙ US9570901036

SecurityWABC / Westamerica Bancorporation
InstitutionNorthern Trust Corp
Latest Disclosed Ownership288,977 shares
Latest Disclosed Value $ 15,070,150
Northern Trust Corp reports 0.52% increase in ownership of WABC / Westamerica Bancorporation

On May 14, 2026 - Northern Trust Corp filed a 13F-HR form disclosing ownership of 288,977 shares of Westamerica Bancorporation (US:WABC) valued at $15,070,151 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 287,469 shares of Westamerica Bancorporation. This represents a change in shares of 0.52% during the quarter. The current value of the position is $16,275,185 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)
2026-05-14 2026-03-31 13F WESTAMERICA BANCORPORATION COM 957090103 288,977 1,508 0.52 15,070 9.61 0.0004
2026-02-17 2025-12-31 13F WESTAMERICA BANCORPORATION COM 957090103 287,469 -21,992 -7.11 13,750 -11.12 0.0004
2025-11-14 2025-09-30 13F WESTAMERICA BANCORPORATION COM 957090103 309,461 -12,177 -3.79 15,470 -0.71 0.0005
2025-08-13 2025-06-30 13F WESTAMERICA BANCORPORATION COM 957090103 321,638 -68,045 -17.46 15,580 -21.03 0.0021
2025-05-13 2025-03-31 13F WESTAMERICA BANCORPORATION COM 957090103 389,683 -4,315 -1.10 19,730 -4.55 0.0029
2025-02-14 2024-12-31 13F WESTAMERICA BANCORPORATION COM 957090103 393,998 59,325 17.73 20,669 24.97 0.0029
2024-11-13 2024-09-30 13F WESTAMERICA BANCORPORATION COM 957090103 334,673 -7,699 -2.25 16,540 -0.46 0.0027
2024-08-14 2024-06-30 13F WESTAMERICA BANCORPORATION COM 957090103 342,372 -8,565 -2.44 16,615 -3.14 0.0028
2024-05-14 2024-03-31 13F WESTAMERICA BANCORPORATION COM 957090103 350,937 -140,321 -28.56 17,154 -38.10 0.0030
2024-02-13 2023-12-31 13F WESTAMERICA BANCORPORATION COM 957090103 491,258 -51,876 -9.55 27,712 17.97 0.0050
2023-11-13 2023-09-30 13F WESTAMERICA BANCORPORATION COM 957090103 543,134 -7,075 -1.29 23,491 11.47 0.0045
2023-08-11 2023-06-30 13F WESTAMERICA BANCORPORATION COM 957090103 550,209 32,352 6.25 21,073 -8.14 0.0040
2023-05-15 2023-03-31 13F WESTAMERICA BANCORPORATION COM 957090103 517,857 28,142 5.75 22,941 -20.61 0.0045
2023-02-13 2022-12-31 13F WESTAMERICA BANCORPORATION COM 957090103 489,715 5,757 1.19 28,898 14.19 0.0061
2022-11-14 2022-09-30 13F WESTAMERICA BANCORPORATION COM 957090103 483,958 2,443 0.51 25,307 -5.58 0.0058
2022-08-12 2022-06-30 13F WESTAMERICA BANCORPORATION COM 957090103 481,515 4,567 0.96 26,802 -7.11 0.0057
2022-05-13 2022-03-31 13F WESTAMERICA BANCORPORATION COM 957090103 476,948 13,571 2.93 28,855 7.87 0.0051
2022-02-08 2021-12-31 13F WESTAMERICA BANCORPORATION COM 957090103 463,377 442 0.10 26,751 2.71 0.0044
2021-11-15 2021-09-30 13F WESTAMERICA BANCORPORATION COM 957090103 462,935 14,169 3.16 26,046 0.02 0.0046
2021-08-13 2021-06-30 13F WESTAMERICA BANCORPORATION COM 957090103 448,766 4,563 1.03 26,042 -6.62 0.0046
2021-05-12 2021-03-31 13F WESTAMERICA BANCORPORATION COM 957090103 444,203 16,406 3.83 27,887 17.90 0.0052
2021-02-11 2020-12-31 13F WESTAMERICA BANCORPORATION COM 957090103 427,797 -50,776 -10.61 23,653 -9.06 0.0046
2020-11-16 2020-09-30 13F WESTAMERICA BANCORPORATION COM 957090103 478,573 -10,278 -2.10 26,010 -7.33 0.0057
2020-08-14 2020-06-30 13F WESTAMERICA BANCORPORATION COM 957090103 488,851 6,203 1.29 28,068 -1.06 0.0066
2020-05-14 2020-03-31 13F WESTAMERICA BANCORPORATION COM 957090103 482,648 -1,079 -0.22 28,369 -13.46 0.0081
2020-02-14 2019-12-31 13F WESTAMERICA BANCORPORATION COM 957090103 483,727 -2,167 -0.45 32,783 8.51 0.0073
2019-11-13 2019-09-30 13F WESTAMERICA BANCORPORATION COM 957090103 485,894 23,849 5.16 30,212 6.13 0.0072
2019-08-13 2019-06-30 13F WESTAMERICA BANCORPORATION COM 957090103 462,045 24,913 5.70 28,467 5.38 0.0068
2019-05-13 2019-03-31 13F WESTAMERICA BANCORPORATION COM 957090103 437,132 15,359 3.64 27,014 15.03 0.0067
2019-02-12 2018-12-31 13F WESTAMERICA BANCORPORATION COM 957090103 421,773 4,076 0.98 23,484 -6.54 0.0066
2018-11-14 2018-09-30 13F WESTAMERICA BANCORPORATION COM 957090103 417,697 7,752 1.89 25,128 8.46 0.0061
2018-09-18 2018-06-30 13F/A-1 WESTAMERICA BANCORPORATION COM 957090103 409,945 -18,756 -4.38 23,167 -6.95 0.0059
2018-08-14 2018-06-30 13F WESTAMERICA BANCORPORATION COM 957090103 411,661 -17,040 23,264
2018-05-09 2018-03-31 13F WESTAMERICA BANCORPORATION COM 957090103 428,701 -2,042 -0.47 24,898 -2.94 0.0065
2018-02-14 2017-12-31 13F WESTAMERICA BANCORPORATION COM 957090103 430,743 -3,706 -0.85 25,651 -0.84 0.0065
2017-11-13 2017-09-30 13F WESTAMERICA BANCORPORATION COM 957090103 434,449 -4,776 -1.09 25,868 5.09 0.0067
2017-08-11 2017-06-30 13F WESTAMERICA BANCORPORATION COM 957090103 439,225 13,810 3.25 24,614 3.63 0.0069
2017-05-12 2017-03-31 13F WESTAMERICA BANCORPORATION COM 957090103 425,415 -4,845 -1.13 23,751 -12.28 0.0068
2017-02-13 2016-12-31 13F WESTAMERICA BANCORPORATION COM 957090103 430,260 -44,232 -9.32 27,076 12.15 0.0083
2016-11-09 2016-09-30 13F WESTAMERICA BANCORPORATION COM 957090103 474,492 7,524 1.61 24,142 4.95 0.0075
2016-08-12 2016-06-30 13F WESTAMERICA BANCORPORATION COM 957090103 466,968 -2,404 -0.51 23,003 1.73 0.0075
2016-08-19 2016-03-31 13F/A-1 WESTAMERICA BANCORPORATION COM 957090103 469,372 12,969 2.84 22,611 5.97 0.0075
2016-05-13 2016-03-31 13F Westamerica Bancorp COMM 957090103 469,372 22,864
2016-02-12 2015-12-31 13F Westamerica Bancorp COMM 957090103 456,403 12,037 2.71 21,337 8.05 0.0071
2015-11-12 2015-09-30 13F WESTAMERICA BANCORPORATION COM 957090103 444,366 444,366 0.00 19,748 0.0066
2015-08-13 2015-06-30 13F Westamerica Bancorp COMM 957090103 0 -424,379 -100.00 0 -100.00
2015-05-14 2015-03-31 13F Westamerica Bancorp COMM 957090103 424,379 17,527 4.31 18,336 -8.06 0.0055
2015-02-12 2014-12-31 13F Westamerica Bancorp COM 957090103 406,852 8,873 2.23 19,943 7.71 0.0060
2014-11-13 2014-09-30 13F Westamerica Bancorp COMM 957090103 397,979 -80,228 -16.78 18,515 -25.94 0.0058
2014-08-14 2014-06-30 13F WESTAMERICA BANCORPORATION com 957090103 478,207 -65,170 -11.99 25,001 -14.92 0.0078
2014-05-14 2014-03-31 13F WESTAMERICA BANCORPORATION COMM 957090103 543,377 1,771 0.33 29,386 -3.90 0.0092
2014-02-21 2013-12-31 13F/A-1 WESTAMERICA BANCORPORATION COM 957090103 541,606 -98 -0.02 30,578 13.48 0.0098
2014-02-12 2013-12-31 13F WESTAMERICA BANCORPORATION COM 957090103 541,606 30,578
2013-11-13 2013-09-30 13F WESTAMERICA BANCORPORATION COM 957090103 541,704 -30,610 -5.35 26,945 3.04 0.0095
2013-08-09 2013-06-30 13F WESTAMERICA BANCORPORATION COM 957090103 572,314 572,314 26,149 0.0095
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.