But the Financial Select Sector SPDR ( XLF ) exchange-traded fund was up just 2.9% over the past 12 months, lagging Standard & Poor's 500-stock index by nearly eight percentage points. They rallied, for instance, ahead of a late-September rate hike by the Federal Reserve, only to drop afterward as inflation fears kicked in. A week later, shares were up again in response to a widening of the so-called yield curve--the difference between rates of the 10-year and two-year Treasury notes.