Branch Network
GNB Bank Locations & Branches Grundy Center, Iowa
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GNB Bank operates 9 branches from its headquarters in Grundy Center, IA, .
GNB Bank branch network
All 9 branches are in IOWA, across 7 cities. Grundy Center, IA has the most of its branches, 2. Its largest office by deposits is its main office in Grundy Center, IA, with $178.2M (35.8% of its branch deposits). On June 30, 2025 it had 10 branches, 1 more than in 2026.
GNB Bank at a glance
Its CET1 capital ratio was 15.45% at Q2 2026, comfortably above the 7% level required once the capital conservation buffer is included.
- Total assets, Q2 2026
- $621.3M
- CET1 ratio, Q2 2026
- 15.45%
- Deposit insurance
- FDIC
- Regulator
- Federal Reserve
- Latest call report
- Q2 2026, FFIEC 051
- Established
- 1934
Full financial profile · Is GNB Bank safe? · GNB Bank call report · Routing number
Deposit market share
Share of all FDIC-insured deposits held in each area, from the June 30, 2026 Summary of Deposits. Rank 1 is the largest holder. Shares are by bank charter, not by holding company.
| Area | Rank | Deposit share | Deposits |
|---|---|---|---|
| City: Grundy Center, IA (2 branches) | 1 of 2 | 69.9% | $178.2M |
| State: IA (9 branches) | 55 of 261 | 0.4% | $498.0M |
Ranked by total assets among banks headquartered in the state: Largest banks in Iowa.
Share by county and metro area
GNB Bank's share of FDIC-insured deposits in the counties and metro areas where it has branches, from the June 30, 2026 Summary of Deposits. Up to the ten largest of each are shown, by the bank's deposits. Rank 1 is the largest holder. Banks only: credit unions are not in the Summary of Deposits.
Counties
| County | Rank | Deposit share | Deposits | County total |
|---|---|---|---|---|
| Grundy, IA (3 branches) | 2 of 7 | 21.4% | $203.0M | $947.2M |
| Delaware, IA (1 branch) | 5 of 6 | 12.6% | $115.4M | $917.6M |
| Hardin, IA (2 branches) | 4 of 7 | 8.3% | $95.6M | $1.15B |
| Marshall, IA (1 branch) | 9 of 11 | 3.4% | $47.1M | $1.39B |
| Story, IA (2 branches) | 14 of 21 | 1.2% | $36.9M | $3.10B |
Metro areas
| Metro area | Rank | Deposit share | Deposits | Metro total |
|---|---|---|---|---|
| Waterloo-Cedar Falls, IA (3 branches) | 6 of 23 | 4.4% | $203.0M | $4.65B |
| Marshalltown, IA (1 branch) | 9 of 11 | 3.4% | $47.1M | $1.39B |
| Ames, IA (2 branches) | 19 of 26 | 1.0% | $36.9M | $3.83B |
| Branch | Location | ZIP | Deposits |
|---|---|---|---|
| GNB Bank (main office) | Grundy Center, IA | 50638 | $178.2M |
| Gnb Manchester Branch | Manchester, IA | 52057 | $115.4M |
| Ackley Branch | Ackley, IA | 50601 | $60.7M |
| Marshalltown Branch | Marshalltown, IA | 50158 | $47.1M |
| Story City Office | Story City, IA | 50248 | $36.9M |
| Iowa Falls Downtown Branch | Iowa Falls, IA | 50126 | $34.9M |
| Conrad Office Branch | Conrad, IA | 50621 | $24.9M |
| Timberland Village Branch | Story City, IA | 50248 | $0 |
| Insurance & Investments | Grundy Center, IA | 50638 | $0 |
Source: FDIC Summary of Deposits, June 30, 2026. How the survey works.
Regulator records: FDIC BankFind (cert 14079) · FFIEC NIC profile (RSSD 724744)