It's been quiet for stocks in the final trading week of the year, as is typical, but expect volatility to return early in 2017, particularly in the retail and technology sectors, Goldman Sachs wrote on Thursday. Both groups could see big moves around the Consumer Electronics Show (CES), which runs from Jan 5-8 and is a "historically stock moving event," the investment bank wrote in a note to clients. Goldman, which recently warned that January could also be volatile for health care stocks, added that the options market was not pricing in the potential moves that could result from the event. "Stocks of companies that attend and that are in the food chain have historically been volatile around this event," wrote a team of researchers led by Katherine Fogertey, an options strategist. "While only a few host formal presentations, simply having a presence at CES could be a catalyst for some stocks. We acknowledge certain presentations might be catalysts for a broader array of stocks," the firm added, citing competitors and ones that might be impacted on comments on consumer demand.