S&P 500 exited the summer selloff about a month ago and has resumed record
highs. By contrast, the Nasdaq-100 remained roughly 4% below its June 2 record
as of last week’s close, the last of the major U.S. indices yet to reclaim its
peak. The lag reflects about 10 months of market divergence that has reshaped
index leadership and return dispersion. Timeline: Nasdaq-100 peaked on Oct. 29
and began to unwind; by mid-December the S&P 500 had returned to fresh highs
while Nasdaq-100 failed to regain its record by late January; a spring selloff
temporarily synchronized declines and near-term bottoms, with each index
completing its rebound within a day of the other; a June chip-stock rout became
the watershed, leaving the S&P relatively stable while the Nasdaq-100 remained
under pressure. Market discussion of the split may have intensified in June, but
the divergence has persisted for roughly ten months.
