Notes:

Image description for those without a trading background (probably people searching for DDLC images):
Short selling is the sale of a security that the seller has borrowed in the belief that a security's price will decline, enabling it to be bought back at a lower price to make a profit. In this case, Sayori has borrowed a significant amount of Bitcoin and is betting it will go down. She is also trading with leverage, meaning she has borrowed money from a broker to increase the amount of Bitcoin she can buy. However, this also makes trading more risky, as her losses are multiplied by the leverage amount. If her losses exceed the amount of money she originally had, she will be "liquidated" and lose it all. In this case, Bitcoin went up by over $4000, so Sayori lost all her money!