Get notified when ATTO files again. Create a free account and we'll email you the moment its next filing is analyzed.

Get filing alerts

Red Flags Detected

  • Material Weakness (new) — The company discloses that identifying material weaknesses in internal controls could result in an adverse reaction in the financial markets due to a loss of confidence in the reliability of its consolidated financial statements.
  • Wuxi Apptec (new) — A key contract manufacturer, WuXi AppTec, was designated on the 1260H List on June 8, 2026, which could lead to restrictions under the BIOSECURE Act and disrupt supply.
  • Biosecure Act (new) — The company relies on Chinese CMOs, and the BIOSECURE Act could restrict its ability to work with them, potentially disrupting supply.
ATTO ATTO 424B4

ATTO prices $289M IPO at $17/share; clinical-stage biotech to net $265.1M for pipeline

Filed August 5, 2026 · ~2 min read

Key Changes

  • high

    ATTO is offering 17,000,000 shares at $17.00 per share, raising $289.0M gross; net proceeds to the company are $265.1M.

    The Offering verify on EDGAR →
  • high

    The company plans to use $110-130M for ATTO-1310 Phase 2, $60-80M for ATTO-2306 Phase 2, and the remainder for earlier pipeline and working capital.

    Use of Proceeds verify on EDGAR →
  • high

    ATTO reported a GAAP net loss of $132.6M for the twelve months ended March 31, 2026, and has an accumulated deficit of $129.7M.

    Management's Discussion and Analysis verify on EDGAR →

3 more material changes behind this preview — plus the full narrative summary, section-by-section diffs against the prior filing, and verbatim quotes with EDGAR citations.

Read 3 full reports/month free No card required. Takes 30 seconds.

Want to see a complete report first? Today's free report (WLTH 10-Q) is open in full — no account needed.

Partner

Trade ATTO commission-free

Open an account, get a free stock.

Sign up

Investing involves risk. Free stock terms apply.

Was this report useful?

Figures/quotes linked to EDGAR · Narrative written by AI · Sep 1, 2026 · How we verify