| Suffolk VA City Employees Federal Credit Union | Virginia |
| Sugar Growers Federal Credit Union | Texas |
| Sugar River Bank | New Hampshire |
| Sugar Valley Federal Credit Union | Nebraska |
| SUMA Federal Credit Union | New York |
| Sumitomo Mitsui Trust Bank (U.S.A.) | New Jersey |
| Summit Bank | California |
| Summit Bank | Oregon |
| Summit Bank | Florida |
| Summit Bank of Kansas City | Missouri |
| Summit Bank & Trust | Colorado |
| Summit Community Bank | West Virginia |
| Summit Credit Union | North Carolina |
| Summit Credit Union | Wisconsin |
| Summit Federal Credit Union | Ohio |
| Summit Hampton Roads Federal Credit Union | Virginia |
| Summit National Bank | Wyoming |
| Summit Ridge Credit Union | Missouri |
| Summit State Bank | California |
| Sumner Bank & Trust | Tennessee |
| Sumner National Bank of Sheldon | Illinois |
| Sumter City Credit Union | South Carolina |
| Suncoast Credit Union | Florida |
| Sun Community Federal Credit Union | California |
| Sun Community Federal Credit Union | California |
| Suncomp Employees Federal Credit Union | Virginia |
| SUN Credit Union | Florida |
| Suncrest Bank | California |
| Sundance State Bank | Wyoming |
| Sundown State Bank | Texas |
| Sun East Federal Credit Union | Pennsylvania |
| Sun Federal Credit Union | Ohio |
| Sunflower Bank | Kansas |
| Sunflower Federal Credit Union | Kansas |
| Sunflower U.P. Federal Credit Union | Kansas |
| Sunkist Employees Federal Credit Union | California |
| Sunland Credit Union | Florida |
| Sunlight Federal Credit Union | Wyoming |
| Sunmark Community Bank | Georgia |
| Sunmark Federal Credit Union | New York |
| Sunnyside Credit Union | Utah |
| Sunnyside Federal Savings and Loan Association of Irvington | New York |
| Sun-Pacific Federal Credit Union | California |
| Sunrise Bank | Florida |
| Sunrise Bank Dakota | South Dakota |
| Sunrise Banks | Minnesota |
| Sunrise Family Credit Union | Michigan |
| Sunset Bank & Savings | Wisconsin |
| Sunset Science Park Federal Credit Union | Oregon |
| Sunshine Bank | Florida |
| Sunshine Savings Bank | Florida |
| SunSouth Bank | Alabama |
| Sunstate Bank | Florida |
| Sunstate Federal Credit Union | Florida |
| Suntide Credit Union | Texas |
| SunTrust Bank | Georgia |
| Sunwest Bank | California |
| Sunwest Educational Credit Union | Colorado |
| SunWest Federal Credit Union | Arizona |
| S.U.N.Y. Fredonia Federal Credit Union | New York |
| SUNY Geneseo Federal Credit Union | New York |
| Superior Bank | Missouri |
| Superior Choice Credit Union | Wisconsin |
| Superior Credit Union | Pennsylvania |
| Superior Federal Credit Union | Ohio |
| Superior Municipal Employees Credit Union | Wisconsin |
| Superior National Bank & Trust Company | Michigan |
| Superior Savings Bank | Wisconsin |
| Superior Savings Credit Union | Ohio |
| Surety Bank | Florida |
| Surrey Bank & Trust | North Carolina |
| Susquehanna Valley Federal Credit Union | Pennsylvania |
| SussexBank | New Jersey |
| Sussex County Federal Credit Union | Delaware |
| Sutter Community Bank | California |
| Sutton Bank | Ohio |
| Suwannee River Federal Credit Union | Florida |
| SWC Credit Union | Florida |
| Swedish American Federal Credit Union | Illinois |
| Swedish-American State Bank | Kansas |
| Sweeny Teachers Federal Credit Union | Texas |
| Sweetex Credit Union | Texas |
| Sweet Home Federal Credit Union | New York |
| Sweetwater Federal Credit Union | Wyoming |
| Sweetwater Regional Federal Credit Union | Texas |
| Sweet Water State Bank | Alabama |
| SWE Federal Credit Union | Texas |
| Swemp Federal Credit Union | Texas |
| Swindell-Dressler Credit Union | Pennsylvania |
| Swineford National Bank | Pennsylvania |
| Swisher Trust & Savings Bank | Iowa |
| Sycamore Bank | Mississippi |
| Sycamore Federal Credit Union | Alabama |
| Sylvania Area Federal Credit Union | Ohio |
| Symphony Federal Credit Union | Massachusetts |
| Synchrony Bank | Utah |
| Synergy Bank | Texas |
| Synergy Bank | Louisiana |
| Synergy Federal Credit Union | Texas |
| Synergy Partners Credit Union | Illinois |