Branch offices
0 offices
FINRA: Small firm
CRD #16886 · FINRA BrokerCheck + SEC IAPD
OAK Brook Securities Corp.
According to FINRA BrokerCheck disclosure totals used on PlainAdvisorCheck graded firms, OAK Brook Securities Corp. ranks #2,308 of 20,055 by disclosure count (most disclosures first). OAK Brook Securities Corp. carries 3 BrokerCheck disclosures across 0 branch offices - heavy load for a single-office firm, earning a Grade C.
- Grade C
- Safety grade
- 0
- branch offices
- 3
- disclosures
- #2,308 of 20,055
- disclosure rank · graded
FINRA BrokerCheck disclosure docket
CRD record 16886 OAK Brook Securities Corp.
OAK Brook Securities Corp. · Grade C · 3 disc · 3.00/office · Single-office firm
- CRD 16886
- GRADE C
- DISC 3
- REG 3
- ARB 0
- CIV 0
- BRANCH 0
- PER-OFF n/a
- RANK #2,308 of 20,055
- BOOK Single-office firm
Intensity peers
Nearest same-size peer: A. B. Culbertson and Company (3.00 disc/office)
OAK Brook Securities Corp. ranks #2,308 of 20,055 by disclosure count among graded broker-dealers; heavy load at 3.00 disclosures per office. Verify on FINRA BrokerCheck →
PlainAdvisorCheck rating 3/5 - an editorial, size-normalized signal, not a regulatory determination. Always verify the underlying record on FINRA BrokerCheck before engaging an advisor.
Data updated July 2026
Total disclosures
3 events
On FINRA BrokerCheck
Regulatory events
3 actions
100% of all disclosures
Disclosures per office
- per office
footprint not reported
Disclosure Breakdown
| Disclosure Type | Count |
|---|---|
| Regulatory Events | 3 |
| Arbitrations | 0 |
| Civil Events | 0 |
| Total | 3 |
Counts for OAK Brook Securities Corp. reflect events reported on FINRA BrokerCheck as of July 2026. Disclosures are reported events, not proven violations.
Disclosure category share
Regulatory 3 Arbitration 0 Civil 0
Firm Details
- Firm Size
- Small
- Scope
- INACTIVE
- Formed
- 08/15/1985
- State of Formation
- Illinois
- CRD Number
- 16886
- SEC Number
- 34691
Regulator-heavy mix
OAK Brook Securities Corp. in the heavier-disclosure third
OAK Brook Securities Corp. carries 3 BrokerCheck disclosures across 0 branch offices - a heavier-third raw book among graded firms (#2,308 of 20,055). Regulator-initiated events are 100% of the book (3 regulatory / 0 arbitration / 0 civil).
100% of OAK Brook Securities Corp.'s 3 disclosures are regulator-initiated (3 events). Verify on FINRA BrokerCheck ↗ · how disclosures are interpreted.
Educational summary of OAK Brook Securities Corp.'s disclosure book - not financial advice. Disclosures are reported events, not proven violations; consult a licensed advisor before decisions.
Source: FINRA BrokerCheck & SEC IAPD Public Disclosure Data
Frequently Asked Questions
Where does OAK Brook Securities Corp. sit among graded broker-dealers by disclosure count?
According to FINRA BrokerCheck disclosure totals used on PlainAdvisorCheck graded firms, OAK Brook Securities Corp. ranks #2,308 of 20,055 by disclosure count (most disclosures first). Ordinals match the disclosure-first sort documented on our methodology corpus-placement section. A high disclosure rank is not automatically a finding of wrongdoing; larger firms accumulate more reported events. Always review the underlying FINRA BrokerCheck detail before engaging.
What does a grade of C mean for OAK Brook Securities Corp.?
A grade of C reflects OAK Brook Securities Corp.'s disclosure intensity, its weighted disclosure load per branch office, ranked against other firms of a similar size (single-office firm). It carries 3 total disclosures across 0 branch offices. Review the specific disclosures on FINRA BrokerCheck before engaging.
How many FINRA disclosures does OAK Brook Securities Corp. have?
OAK Brook Securities Corp. has 3 total FINRA disclosures, including 3 regulatory events. Disclosures reflect reported events on FINRA BrokerCheck and do not necessarily indicate proven violations.
How big is OAK Brook Securities Corp.?
OAK Brook Securities Corp. operates 0 branch offices and is classified by FINRA as a small firm (Single-office firm). FINRA BrokerCheck publishes branch-office counts but not a firmwide registered-representative headcount, so PlainAdvisorCheck measures firm size by branch footprint.
Where can I verify OAK Brook Securities Corp.'s disciplinary record?
You can verify OAK Brook Securities Corp.'s full disciplinary history on FINRA BrokerCheck at brokercheck.finra.org using CRD number 16886. BrokerCheck provides detailed information about individual registered representatives, complaints, and regulatory actions.
What is a FINRA disclosure?
A FINRA disclosure is a reported event on a broker-dealer's record, including regulatory actions, customer complaints, arbitration proceedings, and civil court events. Disclosures are part of the public record maintained by FINRA and do not necessarily indicate wrongdoing or proven violations.
Should I avoid OAK Brook Securities Corp. because of its disclosures?
Not necessarily. Larger firms accumulate more disclosures simply because they operate more offices, so PlainAdvisorCheck grades each firm against same-size peers rather than on raw counts. OAK Brook Securities Corp. carries 3 disclosures across 0 branch offices (about 3.00 per office). Review the nature of individual disclosures on FINRA BrokerCheck before making a decision.
Read with this firm
- A. B. Culbertson and Company - 3.00 disclosures/office, nearest single-office firm peer to OAK Brook Securities Corp.'s 3.00
- A. Gary Shilling & Co., Inc. - 3.00 disclosures/office, nearest single-office firm peer to OAK Brook Securities Corp.'s 3.00
- Abner Herrman & Brock, LLC - 3.00 disclosures/office, nearest single-office firm peer to OAK Brook Securities Corp.'s 3.00
- Red Flags in Advisor Records - How to read OAK Brook Securities Corp.'s heavy load disclosure profile without over-reading raw counts.
- Reading BrokerCheck Reports - Parse the 3 disclosures behind OAK Brook Securities Corp.'s Grade C.
- Highest-Risk Firms - Grade D/F firms on the same size-normalized scale as OAK Brook Securities Corp..
- Compare firms - put OAK Brook Securities Corp. next to peers on grade and footprint.
Read our methodology - heavier-disclosure firms: how raw counts and per-office intensity are graded.
Retrieved and formatted by PlainAdvisorCheck from FINRA BrokerCheck public records.
Every figure on PlainAdvisorCheck is rendered directly from FINRA BrokerCheck and SEC IAPD disciplinary records, no number is typed in by an editor. This page draws directly on FINRA BrokerCheck and SEC IAPD data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of July 2026.