Bitcoin (BTC-USD) miner Marathon Digital Holdings (NASDAQ:MARA) stock rose 5% over the weekend on optimism over cryptocurrencies.The stock was due to open at $18.46 per share this morning, its market capitalization over $4.9 billion.Bitcoin prices surged over the weekend. Early today, each coin was worth $63,500. The total value of Bitcoin is now about $1.26 trillion.Crypto Heating UpNot everyone is high on Marathon or crypto. Fintel reports almost 20% of its stock is now being held short. This includes ove ...