Updated April 2026 · FDIC Call Report Q2 2024
Banks in Oak Brook, Illinois
2 FDIC-insured banks call Oak Brook home, with $4.2B in combined assets. The local cohort posts an average Bank Health Score of 74/100 against a Tier 1 capital ratio of 13.49% and an NPL ratio of 1.54%.
Oak Brook, Illinois hosts 2 FDIC-insured banks headquartered locally, with an average BankHealth composite score of 74/100. The largest local bank by assets is Republic Bank of Chicago. City-level banking concentration reflects historical headquarters geography. Many U.S. cities host community banks chartered specifically for local commercial-lending needs, alongside branch operations of national banks that don't appear in the headquartered-here count.
For local depositors, the BankHealth grade is most useful as a triage signal across the locally-headquartered options. Branch-only banks (headquartered elsewhere) appear on the per-bank pages of their parent institution rather than on this city page.
Oak Brook's Banking Market
Oak Brook hosts 2 FDIC-insured banks — a smaller cluster, which usually indicates a community-banking-centric local market. With this few institutions, depositors should pay closer attention to each bank's individual financials rather than relying on cohort averages.
Banks in Oak Brook post an average Bank Health Score of 74/100 — solidly healthy in B territory, broadly in line with the national average for U.S. banks. 0% earn A grades; 0% land in D or F territory. Most local depositors will find any of the top-graded local banks a sound choice on paper.
Local risk indicators look benign: the average Oak Brook bank posts 13.49% Tier 1 capital and a 1.54% NPL ratio. Both readings are consistent with conservatively run institutions; quarter-to-quarter movement is worth monitoring on individual bank pages.
Oak Brook Banking Snapshot
| Banks headquartered or chartered locally | 2 |
| Combined assets | $4.2B |
| Average Bank Health Score | 74/100 |
| Average Tier 1 capital ratio | 13.49% |
| Average NPL ratio | 1.54% |
| Average liquidity ratio | 21.66% |
| Grade distribution (A · B · C · D · F) | 0 · 2 · 0 · 0 · 0 |
All Banks in Oak Brook
| # | Bank | Grade | Score | Assets | Tier 1 Capital | NPL Ratio | Liquidity |
|---|---|---|---|---|---|---|---|
| 1 | Republic Bank of Chicago | B | 77 | $2.8B | 14.43% | 2.82% | 28.69% |
| 2 | Evergreen Bank Group | B | 70 | $1.5B | 12.55% | 0.27% | 14.63% |
For Oak Brook Depositors
FDIC insurance protects deposits at every bank on this list up to $250,000 per depositor, per insured bank, per ownership category — identical coverage regardless of where the bank is located or how it scores on this page. The Bank Health Score is a relative ranking of regulatory cushion, not a guarantee of safety. Confirm your bank's FDIC status and your specific coverage at FDIC.gov before making decisions.
For depositors who hold combined balances above $250,000 across multiple accounts at a single bank, the FDIC's Electronic Deposit Insurance Estimator (EDIE) calculates exactly which dollars are insured. Account titling — joint, individual, retirement — affects coverage. Federal regulators publishing rules at the OCC and the FDIC update guidance periodically; FDIC.gov is the authoritative source.
How These Scores Are Calculated
Every bank on this page earns a Bank Health Score from four FDIC Call Report inputs: Tier 1 capital ratio (35%), NPL ratio inverted (30%), liquidity ratio (25%), and return on assets (10%). The composite is reported as a 0–100 score and an A–F letter grade. Data flows from the FDIC BankFind API and the FFIEC Call Report archive. Read the full methodology.
Frequently Asked Questions
How many banks are in Oak Brook?
2 FDIC-insured banks are chartered or headquartered in Oak Brook, Illinois, holding $4.2B in combined assets. Oak Brook hosts 2 FDIC-insured banks — a smaller cluster, which usually indicates a community-banking-centric local market. With this few institutions, depositors should pay closer attention to each bank's individual financials rather than relying on cohort averages.
What is the average bank health score in Oak Brook?
Banks in Oak Brook post an average Bank Health Score of 74/100 — solidly healthy in B territory, broadly in line with the national average for U.S. banks. 0% earn A grades; 0% land in D or F territory. Most local depositors will find any of the top-graded local banks a sound choice on paper. The local cohort averages a Tier 1 capital ratio of 13.49% and an NPL ratio of 1.54%.
Are banks in Oak Brook riskier than the national average?
Local risk indicators look benign: the average Oak Brook bank posts 13.49% Tier 1 capital and a 1.54% NPL ratio. Both readings are consistent with conservatively run institutions; quarter-to-quarter movement is worth monitoring on individual bank pages.
Are deposits at Oak Brook banks FDIC-insured?
Every bank on this page is FDIC-insured, which protects deposits up to $250,000 per depositor, per insured bank, per ownership category. Insurance is identical regardless of bank size or location. Verify your specific coverage at FDIC.gov, particularly if you hold balances above the $250,000 limit.
Where does this data come from?
All bank financials on this page are pulled from the FDIC BankFind API, which sources directly from quarterly Call Reports filed with the FFIEC. Health Scores are computed from a transparent four-factor formula (Tier 1 capital 35%, NPL ratio 30%, liquidity 25%, ROA 10%). All data is U.S. government public domain.
Sources: FDIC BankFind API ( banks.data.fdic.gov); FFIEC Call Reports ( cdr.ffiec.gov/public); OCC ( occ.gov). Public domain.
Last updated 2026-04-06 · Data covers 2 Oak Brook banks. Informational only; not investment advice. Verify FDIC insurance directly at FDIC.gov.