$BTC
Bitcoin OG Keeps Doubling Down on His Short"
"Doubling down" in this context means to increase a commitment or risk, often by increasing the size of an existing trade, despite it currently being at a loss.
Here are a few options for replacement words/phrases that maintain the meaning and fit the finance/trading context:
Escalating (More formal, implies increasing in scale)
Augmenting (A good fit, means to make something greater in size or value)
Increasing (Simple and direct)
Scaling Up (Very common trading term for adding to a position)
Ramping Up (Already used later in the post, but also works here: "is once again ramping up his bearish bet")
Fortifying (Implies strengthening his conviction/position)
The best replacements to keep the professional, high-impact trading tone are Escalating or Augmenting. Scaling Up is also an excellent, contextually accurate choice.