Net change is the difference between a prior trading period’s closing price and the current trading period’s closing price for a given security. For stock prices, net change is most commonly referring to a daily time frame, so the net change can be positive or negative for the given day in question. Though the net change for stocks and most securities is quoted in U.S. Dollars when reported by financial media, the net change can be calculated and quoted in any denomination depending on what is being traded.