They struck a deal: if nostr:npub1sg6plzptd64u62a878hep2kev88swjh3tw00gjsfl8f237lmu63q0uf63m Dorsey ever wanted to cash out, Musk would pay him the original purchase price of $54.20 for the shares. 
https://www.axios.com/2023/09/12/elon-musks-secret-deal-jack-dorsey-walter-isaacson-twitter?utm_source=substack&utm_medium=email