Bitcoin fell 13 percent on Sunday after the world’s biggest and best-known cryptocurrency suffered another sell-off that left it down nearly 50 percent from the year’s high. Bitcoin fell to $32,601 at 1800 GMT (2 p.m. ET), losing $4,899.54 from its previous close. It hit a high for the year of $64,895.22 on April 14. Ether, the coin linked to the ethereum blockchain network, dropped 17 percent to $1,905 on Sunday, losing $391.31 from its previous close. Bitcoin markets operate 24/7, setting the stage for price swings at unpredictable hours. “Many point to bitcoin’s volatility as untenable,” wrote RBC Capital Markets’ Amy Wu Silverman in a research note published on Saturday. “Indeed, Bitcoin makes severe and dizzying swings.” Bitcoin had been under pressure after a series of tweets last week by billionaire Tesla Chief Executive and cryptocurrency backer Elon Musk, over his reversal on Tesla accepting bitcoin as payment. In addition, on …