Bitcoin onchain activity surges to yearly high as Coldcard attack unfolds
Bitcoin onchain activity has reached its highest level of 2026 as researchers have linked the surge to the ongoing Coldcard wallet exploit, warning that similar spikes have historically coincided with local market turning points. K33 Research said nearly 890,000 BTC has moved onchain over the past seven days, the highest seven-day active supply recorded this year, even as Bitcoin has continued trading within one of its tightest price ranges in recent years. The research note arrives as investigators continue expanding the scope of the Coldcard hardware wallet breach. Galaxy Research said on Tuesday that at least 15 different attackers have now exploited the vulnerability, while its latest confirmed estimate stands at 1,596 BTC stolen from roughly 7,300 addresses across three verified attack waves. The firm added that losses could reach around 2,055 BTC, or about $130 million, if a fourth suspected wave is confirmed through additional victim reports. Although earlier blockchain observations suggested larger losses, Galaxy said it refined its estimates after separating confirmed victim reports from suspected onchain activity. The research team also said about 90% of the stolen Bitcoin has not moved since the attacks, giving investigators additional time to monitor the funds while coordinating with cryptocurrency exchanges, blockchain security firms