The final trading week of the year is arriving with investors more concerned about defensive positioning than whether the stock market can muster a Santa Claus rally. Stocks were mostly lower in the past week, with the S & P 500 down about 0.6% as of Friday morning. The Nasdaq's losses were greater, with the technology sector helping to lead the losers with a roughly 2.5% decline. The worst sector was consumer discretionary, while defensive groups such as health care, consumer staples and utilities were the best performers of the week. After today, there are just four trading days left...