---
schema_version: "secwatch.filing_event.v1"
accession: "0001466593-25-000091"
form_type: "8-K"
ticker: "OTTR"
cik: "0001466593"
company_name: "Otter Tail Corp"
filed_at: "2025-06-05T23:59:59+00:00"
generated_at: "2026-05-19T21:43:08.573622+00:00"
event_type: "regulatory"
sentiment: "neutral"
materiality_score: 0.55
calibrated_materiality_score: 0.55
confidence: "high"
source: SEC EDGAR
---

# Otter Tail Power files $5.7M annual revenue increase request with South Dakota PUC

## Summary
- Requested net annual revenue increase of $5.7M (12.5%) from South Dakota general rates, filed June 4, 2025.
- Proposed rate of return on rate base 8.29%, ROE 10.8%, equity ratio 53.54% of total capital.
- Changes include moving cost/investment recovery from riders into base rates.
- Rates effective upon SDPUC final disposition or 180 days from filing, subject to refunds.

## SEC filing metadata
- accession: 0001466593-25-000091
- form_type: 8-K
- ticker: OTTR
- cik: 0001466593
- company_name: Otter Tail Corp
- filed_at: 2025-06-05T23:59:59+00:00
- event_type: regulatory
- sentiment: neutral
- materiality_score: 0.55
- calibrated_materiality_score: 0.55
- confidence: high
- sec_items: 8.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1466593/000146659325000091/0001466593-25-000091-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1466593/000146659325000091/ottr-20250604.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001466593-25-000091
- JSON: https://secwatch.observer/filing/0001466593-25-000091.json
- Plain text: https://secwatch.observer/filing/0001466593-25-000091.txt

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