Defying naysayers, Bitcoin’s price surged above $4,500 for the first time early Thursday to reach a market value of $73.6 billion. While the cryptocurrency has since pared some of its gains, falling to $4,453 by midday Thursday, it’s risen by about $1,000 in the past nine days. The currency’s total market value jumped $17 billion in the same period, thanks in part to the optimism traders have around plans to help Bitcoin eventually go mainstream. This includes speedier transactions, starting with its software update—dubbed Segwit2x—earlier this month. les mer her