MicroStrategy Inc. shares extended their recent slide on Wednesday, breaching their 200-day exponential moving average and touching their lowest level in four months. The software maker—widely viewed as a proxy for Bitcoin because of its sizable cryptocurrency holdings—has now fallen about 21% in the past 30 days, placing the stock in bear-market territory. The technical breakdown adds to pressure on a stock that had rallied earlier in the year alongside digital-asset prices. Traders said the loss of the long-term support line could spur further selling unless Bitcoin stabilises, potentially increasing volatility for both assets.