Steve Ballmer admits he was defrauded by founder Joseph Sanberg, writes angry letter at sentencing

Joseph Sanberg, a founder whom Microsoft's former CEO Steve Ballmer backed as an investor, pleaded guilty to fraud. Ballmer responded by writing a letter at Sanberg's sentencing, detailing the financial and personal harm he suffered as a victim of the scheme.

Ballmer's letter, made public during sentencing, describes feeling 'duped and silly' — a rare admission from one of tech's most prominent investors that his due diligence failed to catch a fraudulent operator before money was lost.

For other investors and business professionals: this signals that fraud can happen even with experienced, well-resourced backers doing the vetting. It's a reminder to scrutinize founders carefully, regardless of their track record or credibility, since no investor is immune to deception.