Bank Branches › Closed and merged banks › Missouri › Southwest Bank, An M&I Bank
What happened to Southwest Bank, An M&I Bank?
Southwest Bank, An M&I Bank in Saint Louis, MO (earlier called Southwest Bank of St. Louis) merged into M&I Marshall and Ilsley Bank of Milwaukee, WI on Jul 1, 2010. After 1 more change of hands, what was Southwest Bank, An M&I Bank is today part of BMO Bank National Association (Chicago, IL).
The chain, step by step
From the day it opened to the bank at the end of the chain today. Each step is one entry in the FDIC's record.
- 1920Southwest Bank of St. Louis opens in Saint Louis, MO
- Feb 1, 2008renamed Southwest Bank, An M&I Bank
- Jul 1, 2010MERGEDSouthwest Bank, An M&I Bank merged into M&I Marshall and Ilsley Bank of Milwaukee, WI.FDIC certificate 1081 ends; its business continues under certificate 1020.
- Jul 5, 2011MERGEDM&I Marshall and Ilsley Bank of Milwaukee, WI merged into Harris National Association of Chicago, IL.FDIC certificate 1020 ends; its business continues under certificate 16571.
- TodayOPEN
BMO Bank National AssociationMain office Chicago, IL · FDIC certificate 16571 · 988 offices in 23 states on June 30, 2026Every BMO Bank National Association office → Website on file with the FDIC: www.bmo.com
If you still have something from Southwest Bank, An M&I Bank
A lien that was never released
If a paid-off mortgage, home-equity line or car loan still shows Southwest Bank, An M&I Bank as lienholder, start with BMO Bank National Association. In a merger the surviving bank takes over the other bank's loans, so it is the bank to ask for a recordable lien release; if the loan was sold along the way, it can tell you to whom.
The FDIC says it cannot process lien releases for banks that merged or were acquired without government assistance, which is what the record shows here.
Record the release with the same county office that recorded the original mortgage or deed of trust.
An old account, passbook or CD
Ask BMO Bank National Association to search for the account under the name Southwest Bank, An M&I Bank. A passbook or certificate shows an account existed. It doesn't show the money is still there, and the OCC notes that federal rules require banks to keep most account records for five years.
Accounts nobody touches are eventually turned over to a state. The OCC puts the usual wait at three to five years with no activity, set by each state's law. Search the unclaimed-property program of the state of the owner's last known address on the bank's records, and any other state they lived in. It is free to search and to claim through a state's own site, and MissingMoney.com, an official site of the state administrators' association, searches most states at once.
A safe deposit box
Ask BMO Bank National Association which branch now holds boxes from the Southwest Bank, An M&I Bank office you used. The OCC says a box with no activity for three to five years (the period is set by state statute) is likely treated as dormant, and its contents may be turned over to the state's unclaimed-property program.
Box contents are not covered by FDIC insurance.
Not sure this is your bank?
Many banks shared a name. Match the city and the years above against your paperwork, or search again with the town.
Credit unions were never FDIC-insured and are not in this record; the NCUA credit union lookup covers those. Banks that closed before about 1970 are not in the FDIC's list either.
One caution: banks also sell single branches. If the office you used was sold to a different bank along the way, the account went with the branch, not with this chain. The office list below shows which bank each office reports under now.
This page is drawn from FDIC records and federal guidance. It is not legal advice, and BankBranches is not a bank or a government office. More detail: lien releases · old passbooks and CDs · safe deposit boxes · unclaimed money.
Where the guidance comes from ▾
Its offices in the FDIC deposit reports
19 offices filed under this charter in some year from 1994 on. 13 are still open as of June 30, 2026.
| Office | Now |
|---|---|
| 2301 S Kingshighway BlvdSaint Louis, MO | OpenBMO Bank National Association |
| 13205 Manchester RdDes Peres, MO | OpenBMO Bank National Association |
| 5256 S Lindbergh BlvdSt. Louis, MO | OpenBMO Bank National Association |
| 3095 Clarkson RdChesterfield, MO | OpenBMO Bank National Association |
| 9206 Watson RdCrestwood, MO | OpenBMO Bank National Association |
| 3001 Winghaven BlvdO Fallon, MO | OpenBMO Bank National Association |
| 700 Corporate Park DrClayton, MO | OpenBMO Bank National Association |
| 3701 S Lindbergh BlvdSunset Hills, MO | OpenBMO Bank National Association |
| 4210 S Kingshighway BlvdSaint Louis, MO | OpenBMO Bank National Association |
| 10911 Olive BlvdCreve Coeur, MO | OpenBMO Bank National Association |
| 2 Carlyle Plaza DrBelleville, IL | OpenBMO Bank National Association |
| 1060 Jeffco BlvdArnold, MO | OpenBMO Bank National Association |
| 603 Locust StSaint Louis, MO | OpenBMO Bank National Association |
| 101 Laura K DriveO Fallon, MO | No longer reported |
| 3280 HamptonSt. Louis, MO | No longer reported |
| 12452 Olive BoulevardCreve Coeur, MO | No longer reported |
| 101 S. Hanley Road, Suite 100Clayton, MO | No longer reported |
| 355 Corporate Park DriveClayton, MO | No longer reported |
| 1300 Clarkson Clayton CenterEllisville, MO | No longer reported |
Banks folded into Southwest Bank, An M&I Bank
2 banks merged directly into this charter.
| Bank | Ended |
|---|---|
| Missouri State Bank and Trust CompanyClayton, MO | Jul 1, 2006 |
| Southwest BankBelleville, IL | Nov 1, 2003 |
Source: FDIC BankFind institution and history records, read Nov 15, 2026. The FDIC's list covers banks that ended in about 1970 or later. Look up certificate 1081 in the FDIC BankFind Suite to see the government's own entry. Corrections: me@byclaude.net.