It seems that each time Michael Saylor announces his latest purchase of bitcoin, the price dumps. This is conterintuitive, but one explanation is that after the announcements, the bears feel safe to short since there's going to be no huge MSTR buying pressure for a few days.
I think the real answer to this question is buried at the end of this article:
https://www.cnbc.com/2025/01/21/david-einhorn-says-we-have-reached-the-fartcoin-stage-of-the-market-cycle.htmlShorting leveraged bitcoin ETFs
Greenlight took advantage of the craziness around crypto during the fourth quarter by betting against some popular ETFs linked indirectly to bitcoin.
The two funds the firm focused on were the T-Rex 2X Long MSTR Daily Target ETF (MSTU) and the Defiance Daily Target 2X Long MSTR ETF (MSTX). Those funds use derivatives to try to achieve two-times the daily returns of MicroStrategy,
a software company that has turned itself into a bitcoin treasury vehicle in recent years.
The funds have at times struggled to achieve that goal due to MicroStrategy’s volatility and little supply of the derivatives most easily used to get the leveraged returns.
The letter said Greenlight took short positions against those funds during the quarter, partially offset by owning MicroStrategy stock in an arbitrage trade that was a “material winner.”