US equity markets retreated to close out a volatile week of trading, with Friday night (17 September) a “quadruple witching” session - the simultaneous expiration of individual stock options, stock-index options, stock-index futures and single-stock futures – which brought some additional volume and volatility - Dow fell -166-points or -0.48% . The broader S&P500 lost -0.91% to 4,432.99, with the index slipping below its 50-day moving average of ~4,436.37 for the first time since 18 June. Materials (down -2.06%) led ten of the eleven primary sectors lower, with Utilities (down -1.59%), Information Technology (down -1.52%), Communication Services (-1.27%) and Industrials (-1.05%) all down over >1%. Health Care (up +0.07%) was the only primary sector to eke out a gain. The Nasdaq -0.91%. The small capitalisation Russell 2000 edged +0.18% higher.