(Bloomberg) — Cryptocurrencies shed roughly $300 billion in value this week as a wave of leveraged bets unraveled, battering the sector’s biggest tokens and dragging market sentiment to its weakest point since early summer. Ether, the world’s second-largest cryptocurrency, led the rout with its steepest weekly decline since June. The token has dropped about 12%, sliding below the $4,000 mark — a level traders had widely seen as a crucial line of support. Bitcoin, the market bellwether, wasn’t spared eithe ...