The equal-weight S&P 500 has lost 30% against cap weight since April 2015

The equal-weight S&P 500, held through RSP, has lost 30.4% against the cap-weighted index, held through SPY, since April 6, 2015, counting dividends on both sides. Over the last three years it has lost 15.4%, and over the last year 3.8%. In weekly closes the ratio is just above its lowest reading since RSP launched in 2003, set on May 15, 2026. Both funds hold the same 500 companies. The difference is weighting: in SPY the largest companies count for most of the result, and in RSP each counts the same.

On a longer record, built from Ken French’s data on the largest US stocks weighted both ways since 1929, the three-year change through August was −15.1%, in the lowest 3% of all readings, and January 2026 set the record at −21.9%. After the narrowest tenth of readings, the market returned a median 3.5% a year over the next three years, against 11.7% for all months, and equal weight beat cap weight by a median 4.8 points a year. Those readings come from only six independent periods, and 2020 was an exception. The chart makes no forecast.