Bitcoin’s BTC$64,221.99 booming options market has undergone a notable shift in positioning that could slow the largest cryptocurrency’s ascent above $70,000. That change is tied to open interest in options, a metric that gauges the dollar value locked in the number of call — that is, bullish — and put, or bearish, contracts at various strike levels. Call options at $70,000 are currently the most popular, with open interest of $1.63 billion, according to data source Metrics. The option is a bet that BTC’s price will rise above that level before the contract expires.