Kabushiki Buta Yarou, Isekai de Tsue ni Naru.

A brilliant but reclusive female investor has spent her life caring about only one thing: making money. With an extraordinary talent for trading stocks, she has little interest in other people and is perfectly content profiting for herself. That changes when her beloved younger sister is involved in a terrible accident. Desperate to save her, the investor is given an unbelievable opportunity and sent to another world, where she's tasked with earning an enormous fortune if she wants to save her sister's life. There is, however, one particularly strange complication: after arriving in the fantasy world, she discovers that she hasn't reincarnated as a powerful warrior, beautiful noblewoman, or legendary magician. She's become a staff. Unable to rely on a human body but still possessing the f...