The form 10-Q contains a corporation's quarterly financial statements. This form can be found on a corporation's website. Eventually the financial information can be found everywhere — such as Yahoo Finance — but if I want the information as soon as it is released I go to the company's website. The form 10-Q is roughly 60 pages long. I might have to dig through it to find the financial statements.
Consider for example a stock I own in my portfolio, Apple Inc. (AAPL). On www.apple.com there isn't a link for investor relations. But if I click Site Map at the bottom of the page, that sends me to a page with hundreds of links including one labeled Investors. This is Apple's investor relations page. Investor news will show a press release of the quarterly results and the actual SEC filing called Form 10-Q.
I read both. The press release is a breezy summary of profit results from the company's point of view. Form 10-Q is longer and more tedious to read. But it is more reliable in that it may contain any bad news that the company didn't emphasize in the press release.
