This is the type of financial jargon that makes us cringe. “Risk” is supposed to be a stock because, well, to invest in a company’s stock is risky. “Rally” is when stocks, or other asset prices, rise in value. So, a “risk rally” is a trading session when most stocks move up in price. The way to say this is in human English: investors are buying stocks in many sectors, and they are increasing in value as a result.