I am quite certain that it is more complicated than what it appears to be for public companies similar to Tesla. The unrealized loss will be reflected in their income statement and a public company, they would like this to be positive. This could negatively impact them as a company and on their stock price.
That's clear. The official papers will look bad and they will have to find ways to sugarcoat that in order to keep the investors - big or small - not-too-unhappy, especially as those investors don't know nor care about 4-year cycles, limited supply or technological marvel. But I think that they know that if they sell it's not only the papers looking bad, it'll be the actual reality too.
Also, while the situation may be pretty much similar for all the big investors into bitcoin, the way it's reflected on the quarterly balance may differ and the actions they'll take or not, again, may be different.
That's why, while I think they won't sell, I cannot be sure. And that's why I said it'll be interesting to see what's going to happen next with these companies.