Whether the investors want to sell or not, depends on their strategy. But normally when the prices are at a suitable level only then will the investors sell for a better profit margin, not because they are reluctant to sell. The investors will wait for a suitable price, even after a bull run.
Whenever I realize that the bitcoin price has reached to its top and from there now a decline is expected so in such cases I try my best to sell most of the bitcoin I have. Because I am always expecting that very soon I will get an opportunity to trading bitcoin again in a good price.