Columbia Banking System, Inc.
US ˙ NasdaqGS ˙ US1972361026

SecurityCOLB / Columbia Banking System, Inc.
InstitutionBoston Partners
Latest Disclosed Ownership1,092,044 shares
Latest Disclosed Value $ 30,011,880
Boston Partners reports 6.70% decrease in ownership of COLB / Columbia Banking System, Inc.

On May 11, 2026 - Boston Partners filed a 13F-HR form disclosing ownership of 1,092,044 shares of Columbia Banking System, Inc. (US:COLB) valued at $29,954,767 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 13, 2026 disclosing 1,170,433 shares of Columbia Banking System, Inc.. This represents a change in shares of -6.70% during the quarter. The current value of the position is $31,221,538 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)
2026-05-11 2026-03-31 13F COLUMBIA BKG SYS COM 197236102 1,092,044 -78,389 -6.70 30,012 -8.45 0.0314
2026-02-13 2025-12-31 13F COLUMBIA BKG SYS COM 197236102 1,170,433 -98,405 -7.76 32,781 0.34 0.0339
2025-11-13 2025-09-30 13F COLUMBIA BKG SYS COM 197236102 1,268,838 -982 -0.08 32,671 9.45 0.0335
2025-08-12 2025-06-30 13F/A-1 COLUMBIA BKG SYS COM 197236102 1,269,820 -4,791 -0.38 29,850 -4.75 0.0331
2025-08-07 2025-06-30 13F COLUMBIA BKG SYS COM 197236102 1,269,820 -4,791 29,850 0.0137
2025-05-13 2025-03-31 13F COLUMBIA BKG SYS COM 197236102 1,274,611 3,322 0.26 31,340 -9.58 0.0379
2025-02-11 2024-12-31 13F COLUMBIA BKG SYS COM 197236102 1,271,289 350,229 38.02 34,662 43.71 0.0422
2024-11-12 2024-09-30 13F COLUMBIA BKG SYS COM 197236102 921,060 921,060 24,120 0.0285
2023-02-08 2022-12-31 13F COLUMBIA BKG SYS COM 197236102 0 -499,656 -100.00 0 -100.00
2022-11-09 2022-09-30 13F COLUMBIA BKG SYS COM 197236102 499,656 -35,469 -6.63 14,747 -4.53 0.0216
2022-08-10 2022-06-30 13F COLUMBIA BKG SYS COM 197236102 535,125 8,128 1.54 15,446 -8.36 0.0216
2022-05-10 2022-03-31 13F COLUMBIA BKG SYS COM 197236102 526,997 1,581 0.30 16,855 -2.92 0.0204
2022-02-04 2021-12-31 13F COLUMBIA BKG SYS COM 197236102 525,416 525,416 17,362 0.0209
2021-05-07 2021-03-31 13F COLUMBIA BKG SYS COM 197236102 0 -494,395 -100.00 0 -100.00
2021-02-10 2020-12-31 13F/A-1 COLUMBIA BKG SYS COM 197236102 494,395 -30,384 -5.79 17,748 41.80 0.0276
2021-02-04 2020-12-31 13F COLUMBIA BKG SYS COM 197236102 494,395 -30,384 17,748 10,647.7451
2020-11-13 2020-09-30 13F/A-1 COLUMBIA BKG SYS COM 197236102 524,779 -23,961 -4.37 12,516 -19.11 0.0228
2020-11-09 2020-09-30 13F COLUMBIA BKG SYS COM 197236102 548,740 0 15,473 11,359.0252
2020-08-12 2020-06-30 13F COLUMBIA BKG SYS COM 197236102 548,740 -111,081 -16.84 15,473 -12.19 0.0284
2020-05-13 2020-03-31 13F COLUMBIA BKG SYS COM 197236102 659,821 15,338 2.38 17,622 -32.79 0.0350
2020-02-06 2019-12-31 13F/A-1 COLUMBIA BKG SYS COM 197236102 644,483 518 0.08 26,219 9.48 0.0347
2020-02-05 2019-12-31 13F COLUMBIA BKG SYS COM 197236102 644,483 518 26,219 14,741.0876
2019-11-20 2019-09-30 13F/A-1 COLUMBIA BKG SYS COM 197236102 643,965 -14,326 -2.18 23,948 0.76 0.0324
2019-11-08 2019-09-30 13F COLUMBIA BKG SYS COM 197236102 659,164 873 24,088 0.0319
2019-08-26 2019-06-30 13F/A-1 COLUMBIA BKG SYS COM 197236102 658,291 96,820 17.24 23,768 29.50 0.0312
2019-08-09 2019-06-30 13F COLUMBIA BKG SYS COM 197236102 658,291 96,820 23,768
2019-05-13 2019-03-31 13F/A-1 COLUMBIA BKG SYS COM 197236102 561,471 12,844 2.34 18,354 -7.81 0.0243
2019-05-03 2019-03-31 13F COLUMBIA BKG SYS COM 197236102 561,471 12,844 18,354
2019-02-07 2018-12-31 13F COLUMBIA BKG SYS COM 197236102 548,627 41,502 8.18 19,909 1.26 0.0286
2018-11-14 2018-09-30 13F COLUMBIA BKG SYS COM 197236102 507,125 -3,388 -0.66 19,661 -5.84 0.0228
2018-08-03 2018-06-30 13F COLUMBIA BKG SYS COM 197236102 510,513 11,260 2.26 20,880 -0.30 0.0250
2018-05-04 2018-03-31 13F COLUMBIA BKG SYS COM 197236102 499,253 -13,875 -2.70 20,943 -6.04 0.0253
2018-02-14 2017-12-31 13F/A-1 COLUMBIA BKG SYS COM 197236102 513,128 -24,302 -4.52 22,290 -1.51 0.0263
2018-02-01 2017-12-31 13F COLUMBIA BKG SYS COM 197236102 513,128 -24,302 22,290
2017-11-02 2017-09-30 13F COLUMBIA BKG SYS COM 197236102 537,430 24,004 4.68 22,631 10.61 0.0280
2017-08-02 2017-06-30 13F COLUMBIA BKG SYS COM 197236102 513,426 20,640 4.19 20,460 6.48 0.0260
2017-05-03 2017-03-31 13F COLUMBIA BKG SYS COM 197236102 492,786 -8,545 -1.70 19,214 -14.22 0.0245
2017-02-06 2016-12-31 13F COLUMBIA BKG SYS COM 197236102 501,331 -144 -0.03 22,400 36.52 0.0295
2016-11-09 2016-09-30 13F COLUMBIA BKG SYS COM 197236102 501,475 20,849 4.34 16,408 21.66 0.0229
2016-08-05 2016-06-30 13F COLUMBIA BKG SYS COM 197236102 480,626 5,044 1.06 13,487 -5.22 0.0195
2016-05-12 2016-03-31 13F COLUMBIA BKG SYS COM 197236102 475,582 -21,199 -4.27 14,230 -11.89 0.0210
2016-02-08 2015-12-31 13F COLUMBIA BKG SYS COM 197236102 496,781 -145,742 -22.68 16,150 -19.46 0.0231
2015-11-10 2015-09-30 13F COLUMBIA BKG SYS COM 197236102 642,523 11,375 1.80 20,053 -2.36 0.0306
2015-08-10 2015-06-30 13F COLUMBIA BKG SYS COM 197236102 631,148 62,021 10.90 20,538 24.56 0.0295
2015-05-05 2015-03-31 13F COLUMBIA BKG SYS COM 197236102 569,127 -28,689 -4.80 16,488 -0.11 0.0245
2015-02-09 2014-12-31 13F COLUMBIA BKG SYS COM 197236102 597,816 -15,051 -2.46 16,506 8.55 0.0248
2014-11-12 2014-09-30 13F COLUMBIA BKG SYS COM 197236102 612,867 25,835 4.40 15,206 -1.55 0.0247
2014-08-08 2014-06-30 13F COLUMBIA BKG SYS COM 197236102 587,032 -439 -0.07 15,445 -7.82 0.0259
2014-05-07 2014-03-31 13F COLUMBIA BKG SYS COM 197236102 587,471 -8,375 -1.41 16,755 2.21 0.0306
2014-02-06 2013-12-31 13F COLUMBIA BKG SYS COM 197236102 595,846 -15,492 -2.53 16,392 8.56 0.0336
2013-11-12 2013-09-30 13F COLUMBIA BKG SYS COM 197236102 611,338 -11,572 -1.86 15,100 1.81 0.0364
2013-08-01 2013-06-30 13F COLUMBIA BKG SYS COM 197236102 622,910 622,910 14,831 0.0408
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.