---
schema_version: "secwatch.filing_event.v1"
accession: "0000950170-23-049000"
form_type: "8-K"
ticker: "FISI"
cik: "0000862831"
company_name: "FINANCIAL INSTITUTIONS INC"
filed_at: "2023-09-20T23:59:59+00:00"
generated_at: "2026-06-10T12:45:28.034717+00:00"
event_type: "leadership"
sentiment: "neutral"
materiality_score: 0.4
calibrated_materiality_score: 0.4
confidence: "high"
source: SEC EDGAR
---

# FISI Controller Sonia Dumbleton to retire March 2024; Sandra Byers promoted to Deputy Controller

## Summary
- Sonia Dumbleton, SVP, Controller and PAO, to retire effective March 22, 2024 after 40 years.
- Sandra Byers promoted to Deputy Controller effective October 2, 2023 to lead transition.
- Byers joined FISI as Assistant Controller in May 2021; prior banking experience with M&T, HSBC.
- Dumbleton served as Controller since 2006; also held finance/audit roles since 1984.

## SEC filing metadata
- accession: 0000950170-23-049000
- form_type: 8-K
- ticker: FISI
- cik: 0000862831
- company_name: FINANCIAL INSTITUTIONS INC
- filed_at: 2023-09-20T23:59:59+00:00
- event_type: leadership
- sentiment: neutral
- materiality_score: 0.4
- calibrated_materiality_score: 0.4
- confidence: high
- sec_items: 5.02, 7.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/862831/000095017023049000/0000950170-23-049000-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/862831/000095017023049000/fisi-20230915.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0000950170-23-049000
- JSON: https://secwatch.observer/filing/0000950170-23-049000.json
- Plain text: https://secwatch.observer/filing/0000950170-23-049000.txt

## Key facts
- Executive change
  Sonia M. Dumbleton departed as Senior Vice President, Controller, and Principal Accounting Officer at FINANCIAL INSTITUTIONS INC.
  - Action: retire
  - Role: Senior Vice President, Controller, and Principal Accounting Officer
  source text: On September 15, 2023, Sonia M. Dumbleton notified Financial Institutions, Inc. (the “Company”) that she will retire from her position as Senior Vice President, Controller, and Principal Accounting Officer effective March 22, 2024.
  evidence_url: https://www.sec.gov/Archives/edgar/data/862831/000095017023049000/0000950170-23-049000-index.htm
- Executive change
  Sandra L. Byers was appointed as Deputy Controller at FINANCIAL INSTITUTIONS INC.
  - Action: promoted
  - Role: Deputy Controller
  source text: Over the succeeding six months, the responsibilities of the Controller function will be transitioned to Sandra L. Byers, who has been promoted to Deputy Controller effective October 2, 2023.
  evidence_url: https://www.sec.gov/Archives/edgar/data/862831/000095017023049000/0000950170-23-049000-index.htm

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