Elon Musk has seen his total net worth slip under $700 billion for the first time since December. This follows a 4.8% drop in SpaceX stock on Monday, which continues a downward trend that has seen shares lose nearly half their value since the high point in June. The recent dip resulted in a $29.5 billion loss for Musk, bringing his total fortune to $695.7 billion, just months after he achieved the status of the world's first trillionaire. Musk had previously referred to himself as a "former trillionaire" just last week.