(For a live blog on the U.S. stock market, click or type LIVE/ in a news window.) * FAANG stocks dip in premarket trading * Triple options expiry likely to increase volatility * Futures down: Dow 0.16%, S&P 0.21%, Nasdaq 0.17% (Adds comment, updates prices) Sept 17 (Reuters) - U.S. stock indexes were set for a lower open on Friday, as steady yields for government bonds following an unexpected rebound in retail sales this week pointed to more movement out of heavyweight technology stocks. FAANG stocks, including Apple Inc and Alphabet Inc , some of the largest tech names on Wall Street, fell slightly in premarket trading, while the yields on the benchmark 10-year notes rose slightly. “(It was) a volatile week and a return to value outperformance as ‘buy the dip’ sentiments took hold, but not enough to rescind the recent market weakness,” said Louise Dudley, global equities portfolio manager at the international business of Federated Hermes. Focus is also on a meeting of the Federal Reserve next week, with investors debating if a swathe of strong economic data this week could spur the bank into shortening its timeline for reducing monetary stimulus. The retail sales reading came on the heels of data showing steady factory activity and a cooling in inflation, which suggested the U.S. economic recovery was resilient despite a recent rise in cases of the Delta COVID-19 variant. Losses in major technology stocks had pulled the S&P 500 lower on Thursday, after a jump in bond yields saw investors pivot into sectors most likely to benefit from an economic recovery this year. U.S. S&P 500 E-minis were down 9.5 points, or 0.21%, at 08:00 am ET. Dow E-minis were down 57 points, or 0.16%, while Nasdaq 100 E-minis were down 27 points, or 0.17%. The simultaneous expiration of stock options, stock index futures and index options contracts later in the day, known as triple witching, is also expected to cause volatility through the trading session. While the phenomenon is not new, recent growth in options trading volume and increased awareness of this dynamic has resulted in higher volatility during expirations this year. All three major indexes were headed for small weekly gains. But they were also trading lower for the month due to seasonally weaker trends in September. Monthly losses in the Nasdaq were the least as investors had initially shifted to sectors more resilient to economic disruptions from the pandemic. This trade, however, could unwind in the coming weeks. Among other movers, Invesco Ltd rose 5.2% before the bell on reports that the investment management firm was in talks to merge with peer State Street Corp’s asset-management business. State Street shares rose 0.5%.