Twitter — Mass Firing by Email at 3 AM

Elon Musk’s 80% workforce reduction at Twitter remains the most brutal scale of any tech layoff, outpacing #4 Meta’s cuts by nearly 20 percentage points. Starting November 2022, employees discovered they were terminated when their laptops were remotely locked at 3 AM, a tactic that affected 7,500 workers within weeks. No other company on this list matched the combination of stealth and suddenness: unlike a mass email or a Zoom call, this method left people locked out of their careers with zero prior notice, creating widespread fear and legal backlash.