---
schema_version: "secwatch.filing_event.v1"
accession: "0001104659-21-130467"
form_type: "8-K"
ticker: "RBBN"
cik: "0001708055"
company_name: "Ribbon Communications Inc."
filed_at: "2021-10-27T23:59:59+00:00"
generated_at: "2026-06-28T17:33:13.828063+00:00"
event_type: "earnings"
sentiment: "negative"
materiality_score: 0.6
calibrated_materiality_score: 0.6
confidence: "high"
source: SEC EDGAR
---

# Ribbon Communications Q3 2021 GAAP net loss $0.40/share; revenue $210M, down 9% YoY

## Summary
- Q3 GAAP revenue $210M (down 9% YoY); GAAP net loss $59M vs profit $6M; GAAP EPS loss $0.40 vs +$0.04.
- Non-GAAP net income $16M ($0.11 diluted EPS) vs $22M ($0.14); Adjusted EBITDA $32M vs $43M.
- Supply chain constraints reduced Q3 revenue by ~$9.5M; IP Optical book-to-bill ratio 1.17x.
- Year-to-date revenue $614M (+2%); Non-GAAP diluted EPS $0.31 vs $0.24 (+29%).
- CEO cites strong IP Optical customer wins and 5G/fiber investment tailwinds for 2022 growth.

## SEC filing metadata
- accession: 0001104659-21-130467
- form_type: 8-K
- ticker: RBBN
- cik: 0001708055
- company_name: Ribbon Communications Inc.
- filed_at: 2021-10-27T23:59:59+00:00
- event_type: earnings
- sentiment: negative
- materiality_score: 0.6
- calibrated_materiality_score: 0.6
- confidence: high
- sec_items: 2.02, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1708055/000110465921130467/0001104659-21-130467-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1708055/000110465921130467/tm2131109d1_8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001104659-21-130467
- JSON: https://secwatch.observer/filing/0001104659-21-130467.json
- Plain text: https://secwatch.observer/filing/0001104659-21-130467.txt

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