But yes, they really do! Like anything in the financial markets, we're rarely given a straight answer and no topic has been more confusing than the role fundamentals (or the underlying financial status and performance of a company) play in market valuation. Strictly speaking, people impugn value on a stock or commodity, in that whatever someone is willing to pay for an asset, so is its value. However, financial sustainability is ultimately determined by the fundamentals and those can come a' calling in the most inopportune moment (ie. when you just bought at the top of the market).
Case in point is the mainstream media coverage of China. Early into the new year, we were told that Chinese manufacturing had slowed. This was priced into our domestic markets through volatility, with all three major indices tanking up until recently. That's because some dickhead, or a collective group of dickheads, determined that the deceleration in Chinese PMI wasn't that bad after all. Up went our indices. Now, another preliminary reading of manufacturing data from HSBC has discovered that, no, we were right the first time : things are pretty bad! Add on top of that news that the People's Bank of China withdrew 60 billion yuan (6.6 billion USD) from money markets through bond repurchases will now reconfirm the deflation (both artificial and economic) in the Asian giant.
Some well-researched analysts who are experts in Chinese finance, namely Gordon Chang of Forbes, have been stressing the (poor) fundamentals not for weeks but rather years, yet they are all too often ignored because their thesis doesn't fit the mainstream narrative. Is Mr. Chang able to forecast every dip and dive of the markets across the sea? No, that would be an unreasonable expectation of anyone. But he extracted the numbers and applied quantifiable logic, logic that ultimately dictated that unless something drastic changes, the path of the Chinese economy would take a less than ideal approach.
Fundamentals don't matter only to those whose perspective denies their power. Daytraders, for instance, don't have enough time to look at the fundamentals : they are minute by minute and by default will close their positions by the end of the day. Fundamentals, dare I say, don't matter to your broker or financial advisor either! How come? Because they get paid no matter what goes on in the market (as in, YOUR portfolio)!
But to you, oh, you best believe the fundamentals matter. While the professionals play the short-term game, you are told to play the long-term game. And from that perspective, fundamentals will always dictate the market.