I reason about jumps like this in terms of two components. A &#x27;real&#x27; component and an &#x27;emotional&#x27; component. When a stock moves it moves R% + E%, for real and emotional. The real component in this case seems to be the 200MM+ deal they struck that. R and E are of course unknown, the big investors make their money calculating these values as best they can.<p>Calculating R is hard to do precisely for an amateur (such as me), but E has a nice predictable effect. E mostly consists of the uncertainty of the big investors, and the opportunism of the speculative traders.<p>I mostly do reactive investments based on stock that has just moved in some significant way that companies that I have a lot of fundamental knowledge in (mostly IT industry companies).<p>The way it works is I make a bet on whether the cause for the stock move has any fundamental effect on the future of the company. If I feel I can make that bet more accurately than guys reading the news sitting in cubicles analyzing graphs and industry summaries then I assume I can make a ~5%+ profit on a trade (with a chance of a similar loss of course).<p>For example: The launch of the Kindle Fire by Amazon was a complete flop. This was widely anticipated, I felt very confident in that it would flop. The AMZN stock dropped as people lost confidence (E) in the Fire and I bought when I felt it was pretty much solid that everyone agreed that the Fire had flopped. Unfortunately I was naieve, and a few weeks later Amazon released its earnings report that undeniably confirmed the flop, and E was eliminated, and R adjusted causing another drop. At this point I was in the negative, so there was a lesson for me there. Anyway, my bet was that the Fire was just some largely irrelevant side strategy for Amazon. Sure they invested too much, and their chance for rivalling Apples iPad or whatever insane plan they had was ill conceived, but it was just something they had to try. The big plan of Amazon however did not suffer from this failure. They were still on track to becoming the force of nature they want to be so the lack of confidence (negative E) of the daytraders was in my opinion unjustified. A few months later this showed, the dip of the Fire was gone, and if I sold then I would&#x27;ve made a cool ~10%.<p>I didn&#x27;t sell though as I thought Amazon was a cool company to hold stock in for the long term, so the bet was just a gimmick to get some long term stock for cheap. I ended up making a lot more money on AMZN than I expected as for some reason the fact that Amazon makes a lot of money on AWS was big news to the financial world and slapped a big markup on the stock after which I sold, because I don&#x27;t pretend to actually know what an Amazon stock should really be worth.