---
schema_version: "secwatch.filing_event.v1"
accession: "0001193125-24-162069"
form_type: "8-K"
ticker: "ATRA"
cik: "0001604464"
company_name: "Atara Biotherapeutics, Inc."
filed_at: "2024-06-17T23:59:59+00:00"
generated_at: "2026-06-01T04:06:41.249475+00:00"
event_type: "other_material"
sentiment: "negative"
materiality_score: 0.6
calibrated_materiality_score: 0.6
confidence: "high"
source: SEC EDGAR
---

# Atara Biotherapeutics announces 1-for-25 reverse stock split to comply with Nasdaq listing requirement

## Summary
- Reverse stock split at 1-for-25 ratio effective June 20, 2024 at 12:01 a.m. ET; post-split trading starts same day.
- Outstanding shares reduced from ~122.6M to ~4.9M; fractional shares paid in cash.
- Split authorized by stockholders on June 10, 2024; board set final ratio same day.
- Purpose: regain compliance with Nasdaq $1.00 minimum bid price for continued listing.
- Pre-funded warrants adjusted from 32.15M pre-split to ~1.29M post-split, subject to fractional cash payments.

## SEC filing metadata
- accession: 0001193125-24-162069
- form_type: 8-K
- ticker: ATRA
- cik: 0001604464
- company_name: Atara Biotherapeutics, Inc.
- filed_at: 2024-06-17T23:59:59+00:00
- event_type: other_material
- sentiment: negative
- materiality_score: 0.6
- calibrated_materiality_score: 0.6
- confidence: high
- sec_items: 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1604464/000119312524162069/0001193125-24-162069-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1604464/000119312524162069/d705331d8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001193125-24-162069
- JSON: https://secwatch.observer/filing/0001193125-24-162069.json
- Plain text: https://secwatch.observer/filing/0001193125-24-162069.txt

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