Why has bitcoin dropped so precipitously in the last two weeks? This question comes as the incumbent virtual currency has declined 46% since Nov. 13 and now struggles to sustain a range between $3,900 and $4,000. There is no single answer to this question, but anyone paying attention to the market this year will know a handful of them. One answer is simply that bitcoin was once worth $20,000. The gravity of this number has as much pull to the downside as it does optimism for the upside, however. What was once the fear of missing out quickly turned into the fear of holding the world's riskiest asset at the top of the ... (full story)