RANKING ·
Largest net interest margin improvement in South Dakota
44 of 58 banks in South Dakota that filed for the quarter ended June 30, 2026 are ranked. At least $100 million in total assets and a comparable quarter a year earlier. Institutions with equal values share a rank. Source: FDIC quarterly financial data.
| Rank | Institution | Headquarters | Net interest margin, change over 12 months | Total assets |
|---|---|---|---|---|
| 1 | Campbell County Bank | Herreid, SD | +61 bps | $241 million |
| 2 | Security National Bank of South Dakota | Dakota Dunes, SD | +61 bps | $251 million |
| 3 | First Bank & Trust | Brookings, SD | +56 bps | $4.8 billion |
| 4 | Plains Commerce Bank | Sioux Falls, SD | +48 bps | $1.3 billion |
| 5 | Bankstar Financial | Elkton, SD | +48 bps | $363 million |
| 6 | Bankwest, Incorporated | Pierre, SD | +47 bps | $1.9 billion |
| 7 | Reliabank Dakota | Estelline, SD | +46 bps | $788 million |
| 8 | Black Hills Community Bank N.A. | Rapid City, SD | +44 bps | $490 million |
| 9 | Citizens State Bank of Arlington | Arlington, SD | +44 bps | $153 million |
| 10 | Dacotah Bank | Aberdeen, SD | +43 bps | $4.9 billion |
| 11 | Commercial State Bank of Wagner | Wagner, SD | +41 bps | $260 million |
| 12 | First Dakota National Bank | Yankton, SD | +40 bps | $3.4 billion |
| 13 | Farmers State Bank | Parkston, SD | +36 bps | $255 million |
| 14 | Rivers Edge Bank | Marion, SD | +36 bps | $357 million |
| 15 | Security Bank Midwest | Tyndall, SD | +36 bps | $304 million |
| 16 | The First National Bank in Sioux Falls | Sioux Falls, SD | +35 bps | $2.1 billion |
| 17 | Frontier Bank | Sioux Falls, SD | +34 bps | $349 million |
| 18 | Dnb National Bank | Clear Lake, SD | +30 bps | $124 million |
| 19 | Heartland State Bank | Redfield, SD | +25 bps | $154 million |
| 20 | Pioneer Bank & Trust | Belle Fourche, SD | +25 bps | $1.0 billion |
| 21 | Merchants State Bank | Freeman, SD | +23 bps | $220 million |
| 22 | First Fidelity Bank | Burke, SD | +22 bps | $717 million |
| 23 | Security Savings Bank | Canton, SD | +13 bps | $557 million |
| 24 | Cortrust Bank N.A. | Mitchell, SD | +7 bps | $1.6 billion |
| 25 | First National Bank in Philip | Philip, SD | +6 bps | $458 million |
| 26 | Farmers and Merchants State Bank | Plankinton, SD | +2 bps | $180 million |
| 27 | American Bank & Trust | Sioux Falls, SD | +2 bps | $2.2 billion |
| 28 | One American Bank | Centerville, SD | -5 bps | $285 million |
| 29 | Citibank N.A. | Sioux Falls, SD | -5 bps | $2.0 trillion |
| 30 | First State Bank of Roscoe | Roscoe, SD | -6 bps | $147 million |
| 31 | First Premier Bank | Sioux Falls, SD | -7 bps | $3.6 billion |
| 32 | First Savings Bank | Beresford, SD | -10 bps | $1.6 billion |
| 33 | Wells Fargo Bank N.A. | Sioux Falls, SD | -19 bps | $1.9 trillion |
| 34 | Sunrise Banks N.A. | Sioux Falls, SD | -19 bps | $2.8 billion |
| 35 | Quoin Financial Bank | Miller, SD | -24 bps | $251 million |
| 36 | Anchorage Digital Bank N.A. | Sioux Falls, SD | -28 bps | $1.9 billion |
| 37 | Great Plains Bank | Eureka, SD | -49 bps | $150 million |
| 38 | First National Bank | Oldham, SD | -50 bps | $478 million |
| 39 | Security State Bank | Alexandria, SD | -52 bps | $103 million |
| 40 | First National Bank | Fort Pierre, SD | -52 bps | $2.0 billion |
| 41 | The Bancorp Bank National Association | Sioux Falls, SD | -65 bps | $9.2 billion |
| 42 | U.S. Bank Trust National Association Sd | Sioux Falls, SD | -68 bps | $192 million |
| 43 | 1st Financial Bank USA | Dakota Dunes, SD | -73 bps | $1.4 billion |
| 44 | Pathward N.A. | Sioux Falls, SD | -79 bps | $7.3 billion |
Rankings sort one published measure; they are not an overall judgment of any institution. Methodology · All rankings