Bitcoin holders affected by a Coldcard vulnerability suffered severe losses, with one member of a local Bitcoin community losing 90% of their holdings and a woman interviewed by BTC Sessions losing all of her Bitcoin. BTC Sessions said its team spent several weeks helping affected holders move funds to safer locations and estimated that it protected Bitcoin worth tens of millions of dollars. The experience may be the most serious self-custody incident in Bitcoin’s history, BTC Sessions said, prompting it to reconsider asset custody and identify diversified security measures as a key lesson.