Let us start from the old times, where markets were less liquid. Suppose I hold some stocks of the company XYZ and I want to sell them. Why shall I expect that their price can rise in the next quarter given that company showed good in the current quarter and is likely to do well in the future? I could name at least three reasons for that:
The dividends on these stocks will be higher
If I own enough stocks, the buyer of them can play a role in managing the company
The buyer of stocks will expect that the price will grow even further and wants to speculate on the stocks by selling them for a higher price, say, in a year.
The latter reason is a bit cyclic though: if it would be the only reason to buy a stock - then the only thing determining the price direction would be the expectation of market participants - even not about the company itself, but about the price direction. As a result, in such situation I would not see any connection between the fact how the company does, and how the stock price changes.
At the current moment, there are a lot of companies that do not pay any dividends on their stocks, and there are a lot of investors that buy/sell stocks of these companies in amounts much less to talk about affecting the company's management. I wonder thus, whether for such companies there is no any connection between how company does, and how the stock price moves. Perhaps, that could be illustrated by a dotcom situation 15 years ago. By a fundamental reason for a price change I mean something that does not depend only on the expectation of the market about the stock's price, and is related to the company itself.
Edited: I've just found a very nice and useful discussion here which almost answers my question. At the same time, I would be happy if a more quant-oriented community says its word.