Not "if the fundamentals deteriorate" but like actually a number or event you decided before you bought.
Some of you might not have that number but it's very important. And I'm asking because I couldn't answer it for myself for like 2 years. I'd read an earnings report and see three headlines pointing different directions and decided randomly.
Thankfully I've learned since then, and it's the real line between investing and just holding companies.
So now I write down the exit condition and stuff like that when I'm calm on Thesislock so I don't panic when it reports. And it also helps later to find why you bought if the stock dumps and you wanna panic sell.
So yeah, MSFT is my biggest position, and my condition is to sell half to all of my position depending on whether FCF is falling/rising and by how much, while also considering the price it's at, simple but effective.