ATTO upsizes IPO to 17M shares at $17, lifting net proceeds to $265.1M

Filed August 4, 2026 · Compared to S-1/A Jul 29, 2026 · ~1 min read

Key Changes

• high

  Offering size increased from 12.5M to 17M shares at $17.00 per share, raising estimated net proceeds to $265.1M (or $305.4M with over-allotment).

  Use of Proceeds verify on EDGAR →
• high

  New investors will own 42.9% of the company post-offering (39.5% excluding over-allotment), up from 35.6% previously, while existing holders are diluted to 57.1%.

  Dilution verify on EDGAR →
• medium

  Immediate dilution per share to new investors improves to $7.75 from $7.82, reflecting the higher offering price.

  Dilution verify on EDGAR →