There are several ways to measure relative performance here at StockCharts. Chartists can use ratio charts (XLF:SPY), the StockCharts Technical Rank (SCTR) or Relative Rotation Graphs (RRGs). Chartists can also compare the respective price charts. The chart below shows closing prices for the HealthCare SPDR (XLV), Finance SPDR (XLF) and S&P 500 SPDR (SPY). The red dotted line marks the closing high on March 2nd. Notice that SPY remains well below this high, but XLV and XLF closed above this high on Monday and Tuesday. These are the only two sector SPDRs trading above their March 2nd highs and this is a form of relative strength.