Mar 31, 2026 filings. Quarterly 13F reports arrive up to 45 days after quarter end; this register is filed through May 29, 2026.
276 institutional managers reported holding FIBK for the quarter ended Mar 31, 2026. Together they hold about 91% of shares outstanding; the top 10 hold 56%. 40 opened new positions; 34 closed out. Complete ranked register from SEC 13F filings.
| manager | shares | % out | value (Mar 31, 2026 close) | change | held since |
|---|---|---|---|---|---|
| BlackRock | 13.48M | 13.58% | $450.1M | trimmed -1% | ≤2013 |
| Vanguard Group | 10.05M | 10.13% | $335.7M | unchanged | ≤2013 |
| State Street | 5.89M | 5.94% | $196.7M | added +7.5% | ≤2013 |
| Dimensional Fund Advisors | 5.63M | 5.67% | $188.0M | added +4.3% | ≤2013 |
| First Interstate Bank | 4.65M | 4.69% | $155.4M | unchanged | ≤2013 |
| HoldCo Asset Management, LP (focused) | 3.95M | 3.98% | $131.9M | unchanged | 2025 Q2 |
| Wellington Management | 3.88M | 3.91% | $129.6M | trimmed -33% | 2018 Q2 |
| FMR (Fidelity) | 3.88M | 3.91% | $129.5M | trimmed -18.1% | 2018 Q3 |
| Capital International Investors | 2.29M | 2.31% | $76.5M | trimmed -14.3% | 2025 Q4 |
| Geode Capital | 2.22M | 2.23% | $74.1M | trimmed -0.7% | ≤2013 |
| Victory Capital Management INC | 2.09M | 2.10% | $69.7M | added +0.5% | 2015 Q2 |
| UBS | 1.94M | 1.95% | $64.7M | trimmed -5.6% | ≤2013 |
| Franklin Resources | 1.88M | 1.90% | $62.8M | trimmed -27.6% | 2021 Q3 |
| Bank OF America CORP /DE/ | 1.78M | 1.79% | $59.4M | added +1.4% | ≤2013 |
| Nomura Asset Management International INC. | 1.70M | 1.72% | $56.9M | trimmed -12.3% | 2025 Q4 |
| Morgan Stanley | 1.51M | 1.53% | $50.6M | trimmed -4.1% | ≤2013 |
| MFS Investment Management | 1.27M | 1.28% | $42.5M | trimmed -5.1% | 2021 Q3 |
| First Trust Advisors LP | 1.20M | 1.21% | $40.0M | added +214.9% | 2014 Q1 |
| Charles Schwab Investment Management | 1.18M | 1.19% | $39.5M | added +0.7% | ≤2013 |
| Capital Group (American Funds) | 1.15M | 1.16% | $38.3M | opened | 2026 Q1 |
| BNY Mellon | 976.2k | 0.98% | $32.6M | trimmed -3.1% | ≤2013 |
| Cramer Rosenthal Mcglynn LLC | 914.2k | 0.92% | $30.5M | trimmed -13.2% | 2025 Q3 |
| Northern Trust | 881.3k | 0.89% | $29.4M | added +1.1% | ≤2013 |
| Millennium Management | 781.1k | 0.79% | $26.1M | opened | ≤2013 |
| Punch & Associates Investment Management, INC. | 735.4k | 0.74% | $24.6M | added +1.6% | 2024 Q4 |
| Goldman Sachs | 705.8k | 0.71% | $23.6M | trimmed -7.1% | ≤2013 |
| Leeward Investments, LLC - MA | 632.0k | 0.64% | $21.1M | trimmed -2.7% | 2022 Q1 |
| Villere ST Denis J & CO LLC | 627.0k | 0.63% | $20.9M | added +15.1% | 2024 Q2 |
| Jennison Associates LLC | 586.7k | 0.59% | $19.6M | trimmed -56.7% | 2023 Q2 |
| SEI Investments CO | 465.5k | 0.47% | $15.5M | added +7.4% | 2015 Q3 |
| Principal Financial Group INC | 427.4k | 0.43% | $14.3M | unchanged | 2016 Q4 |
| Aristotle Capital Boston, LLC | 418.3k | 0.42% | $14.0M | trimmed -13.4% | 2024 Q3 |
| Davidson Investment Advisors | 408.4k | 0.41% | $13.6M | trimmed -15.2% | 2021 Q3 |
| Raymond James Financial INC | 331.5k | 0.33% | $11.1M | added +1.1% | 2024 Q4 |
| Invesco | 329.8k | 0.33% | $11.0M | trimmed -10.9% | ≤2013 |
| North Reef Capital Management LP | 325.2k | 0.33% | $10.9M | trimmed -83.5% | 2025 Q3 |
| Public Sector Pension Investment Board | 314.7k | 0.32% | $10.5M | added +1.6% | 2025 Q4 |
| Nuveen | 299.7k | 0.30% | $10.0M | trimmed -2.8% | 2019 Q2 |
| Cambria Investment Management, L.p. | 276.8k | 0.28% | $9.2M | added +12.8% | 2025 Q4 |
| Fisher Investments | 266.0k | 0.27% | $8.9M | unchanged | 2020 Q2 |
| Rhumbline Advisers | 246.9k | 0.25% | $8.2M | trimmed -1% | ≤2013 |
| Legal & General Group PLC | 203.9k | 0.20% | $6.8M | trimmed -6.5% | 2014 Q3 |
| Harbor Capital Advisors, INC. | 200.2k | 0.20% | $6.7M | added +81.5% | 2024 Q3 |
| Creative Planning | 199.6k | 0.20% | $6.7M | added +82% | 2023 Q3 |
| Susquehanna International Group | 190.4k | 0.19% | $6.4M | added +240.9% | 2019 Q3 |
| Swiss National Bank | 173.0k | 0.17% | $5.8M | trimmed -1.6% | ≤2013 |
| Granite Investment Partners, LLC | 172.3k | 0.17% | $5.8M | added +3.1% | ≤2013 |
| Moody Aldrich Partners LLC | 170.3k | 0.17% | $5.7M | opened | 2026 Q1 |
| Ameriprise Financial INC | 165.6k | 0.17% | $5.5M | trimmed -19.8% | 2019 Q1 |
| AQR Capital | 162.2k | 0.16% | $5.4M | trimmed -3.6% | 2024 Q2 |
Largest 50 of 276 shown; the full ranked, searchable register is at boothcheck.com/holders/FIBK. Related filers are grouped using the filings' own included-manager declarations. Historically, several managers opening new positions in the same quarter said almost nothing about the quarter that followed (59,118 cases since 2013). A filed record, not a forecast. Nothing here is investment advice.