human
Is there a way to find out how much a particular stock has gone up or down over a certain time period?
assistant
There are several ways to do this. One is to look at the historical performance of the stock, which can be found on sites such as Yahoo! Finance and Google Finance. Another option is to use an online brokerage service that provides real-time quotes for stocks and other financial instruments. These services typically provide information about the current market value of a stock, its trading volume and any recent news related to the company.