Bitcoin is down nearly 20% from its record high of $126,272.76 in early October. - iStock/MarketWatch photo illustration Bitcoin prices retreated below $100,000 for the first time since June on Tuesday. The pioneering cryptocurrency has struggled since a “flash crash” rocked the crypto space last month. The largest cryptocurrency BTCUSD briefly traded as low as $99,982 in afternoon trading before recouping some losses and bouncing back to $101,269, according to FactSet data. Most Read from MarketWatch ...