Bitcoin traded above US$41K during Monday US time. The price surge began Sunday afternoon US time with a Musk tweet:

It got a renewed push on the news that business software company MicroStrategy made a statement on Monday its readying to buy up to $488m in bitcoin, utilising proceeds from a $500m bond sale it has finalised.

BTC/USD has since dribbled back under $40K

Bitcoin Microstrategy bond sale buy price chart