---
schema_version: "secwatch.filing_event.v1"
accession: "0001193125-24-011252"
form_type: "8-K"
ticker: "MKTX"
cik: "0001278021"
company_name: "MARKETAXESS HOLDINGS INC"
filed_at: "2024-01-19T23:59:59+00:00"
generated_at: "2026-06-06T21:06:23.790282+00:00"
event_type: "leadership"
sentiment: "neutral"
materiality_score: 0.65
calibrated_materiality_score: 0.65
confidence: "high"
source: SEC EDGAR
---

# MarketAxess CFO Gerosa resigns; CEO Concannon named interim CFO effective Feb 1, 2024

## Summary
- CFO Christopher N. Gerosa resigns effective Jan 31, 2024, to accept a position at another company.
- CEO Christopher R. Concannon appointed interim CFO effective Feb 1, 2024, serving as both CEO and interim CFO.
- Michael R. Cianciulli, Head of External Reporting, appointed interim principal accounting officer.
- Board actively conducting a formal search for a permanent CFO.

## SEC filing metadata
- accession: 0001193125-24-011252
- form_type: 8-K
- ticker: MKTX
- cik: 0001278021
- company_name: MARKETAXESS HOLDINGS INC
- filed_at: 2024-01-19T23:59:59+00:00
- event_type: leadership
- sentiment: neutral
- materiality_score: 0.65
- calibrated_materiality_score: 0.65
- confidence: high
- sec_items: 5.02
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1278021/000119312524011252/0001193125-24-011252-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1278021/000119312524011252/d646030d8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001193125-24-011252
- JSON: https://secwatch.observer/filing/0001193125-24-011252.json
- Plain text: https://secwatch.observer/filing/0001193125-24-011252.txt

## Key facts
- Executive change
  Christopher R. Concannon was appointed as interim Chief Financial Officer at MARKETAXESS HOLDINGS INC.
  - Action: appointed
  - Role: interim Chief Financial Officer
  source text: On January 18, 2024, the Board of Directors (“Board”) of the Company appointed Christopher R. Concannon, Chief Executive Officer of the Company, as interim Chief Financial Officer, effective February 1, 2024.
  evidence_url: https://www.sec.gov/Archives/edgar/data/1278021/000119312524011252/0001193125-24-011252-index.htm
- Executive change
  Michael R. Cianciulli was appointed as interim principal accounting officer at MARKETAXESS HOLDINGS INC.
  - Action: appointed
  - Role: interim principal accounting officer
  source text: In addition, on January 18, 2024, the Board appointed Michael R. Cianciulli, the Company’s Head of External Reporting, as interim principal accounting officer of the Company.
  evidence_url: https://www.sec.gov/Archives/edgar/data/1278021/000119312524011252/0001193125-24-011252-index.htm
- Executive change
  Christopher N. Gerosa resigned as Chief Financial Officer at MARKETAXESS HOLDINGS INC.
  - Action: resigned
  - Role: Chief Financial Officer
  source text: On November 6, 2023, MarketAxess Holdings Inc. (the “Company”) was informed by Christopher N. Gerosa, the Company’s Chief Financial Officer, that he will resign from such position effective January 31, 2024, to accept a position with another company.
  evidence_url: https://www.sec.gov/Archives/edgar/data/1278021/000119312524011252/0001193125-24-011252-index.htm

This AI-assisted summary is a reading aid. Review the linked SEC EDGAR filing before relying on any specific claim.