One of the tools on the Fidelity Portfolio page is a summary view of “Your Top & Bottom Movers.” This is helpful for stock and perhaps for some ETF investors, but not so much for mutual funds. Unfortunately, mutual funds (MF) don’t “move” during the day, so you can’t really determine what a MF investment is doing during the day.
If you see an investment is rising quickly, you might want to sell (or buy more.) If an investment is getting hammered, you might want to sell or buy. The decision should be based on your written investment plan, not on the current euphoria or hysteria.
Here is what I do: I click on the position that I am interested in reviewing. Fidelity then takes me to the stock snapshot. One of the choices on the left is “News & Events.” Sometimes there are news items that are hitting or goosing a sector. Sometimes there is news specific to the company. And, of course, there could be an “event” shown like a dividend increase or decrease or a good or bad quarterly earnings report. This is when you don’t let emotion rule your decision. You consider the long-term opportunity as more important than the short-term pain or pleasure. If the stock has gone up due to a potential buy-out by another company, I will probably sell. Those spikes often don’t last long, and I don’t want to wait around to see what might happen.
ETFs don’t often appear in the big movers because they don’t generally move as much as individual stocks. However, if all your investments are ETFs (mine aren’t) then you might get a glimpse of an opportunity if you invest in sector ETFs.