Event-driven, market-neutral test of the index-deletion price-pressure reversal (Harris & Gurel 1986 price-pressure hypothesis; Chen, Noronha & Singal 2004 'The Price Response to S&P 500 Index Additions and Deletions', Journal of Finance). When a stock is removed from the S&P 500, index funds and benchmarked managers must sell it around the effective date, whatever its value. The forced, information-free selling pushes the price below its equilibrium value. Once the selling is finished, the price should partly recover over the following weeks as liquidity providers unwind. Chen-Noronha-Singal report large post-effective recoveries for deletions. Greenwood & Sammon (2022, 'The Disappearing Index Effect') show the effect has shrunk for additions. This test asks whether the deletion reversal survives in 2010-2026, net of costs and hedged against the market. The universe is point in time. Events come only from the platform's historical S&P 500 membership (index_member(), built from fja05680/sp500 + Wikipedia intervals). An event fires on the first daily bar on which a leg that was a member on the previous bar is no longer one. The candidate legs are the 108 former members whose daily USEQ bars continue at least 60 days after a 2010-2026 removal (data_check=ok in sp500_membership.parquet). Acquired or bankrupt names that Yahoo dropped have no post-removal bars, so they never enter. We cannot buy them in reality either, but their absence can bias results upward. Execution: daily bars on a session venue, so a decision at bar N's close fills at bar N+1's open (next_open_fill, supported). No intrabar requirement. Mechanism diversity: this is the factory's first index-reconstitution or forced-flow event strategy. It needs no supplementary feed beyond the membership calendar. It is long/short and runs on USEQ, which holds only 9% of the corpus. It uses about 108 never-used single-stock instruments instead of BTC/majors.