ETF sector leadership continues to shift rapidly.  The most dramatic move of the week came from a semiconductor ETF, which moved from #37 to #5 in the ratings from our TCA-ETF model.  We try to look at both Trend and Cycle, while doing some Anticipation of key swings.  Ideally, we exit positions when new ETF's gain strength, surpassing current holdings.  Over the last few weeks there have been several dramatic changes of sector leadership.  (For new readers, there is a further explanation of our approach at the end of the article.) The sector moves are also a path to deeper understanding of the overall market.  As usual, we shall start with some fundamental factors that underly semiconductor strength. S&P North American Technology-Semiconductors Index Fund (IGW) This week's featured sector is the iShares S&P North American Technology-Semiconductors Index Fund (IGW).  ...