MicroStrategy's leveraged ETF, MSTU, has reached $1 billion in assets under management (AUM) amid the Bitcoin surge.MSTU behaves like a 4x Bitcoin ETF by leveraging MicroStrategy's stock, bypassing US leverage restrictions.MSTU has posted a 225% gain in just six weeks, with a daily trading volume ranking among the top 1% of all ETFs.Some experts warn of potential overvaluation, but investors remain eager to ride MicroStrategy's Bitcoin-centric trajectory.