Bitcoin staged a powerful rally Thursday morning, climbing to a double-digit percentage gain in less than 30 minutes, with market participants unclear about the impetus for the unexpected jump. The value of a single bitcoin BTCUSD, +10.71% reached an intraday peak at $8,055.20, representing a roughly 16% pop in a short period, according to research and data site CoinDesk.com. Most recently, the No. 1 cryptocurrency was up about 12% at $7,788.03. The rally for bitcoin comes after a prolonged period of low volatility where the currency was stuck in a $1,000 range, Thursday's move marks the largest price swing since Feb. 6, when bitcoin bounced off its record low of $5,947.40 to close at $7,700.39.