Mercadolibre Plunges 6.21% on 1.58B-Share Surge Ranks 74th in U.S. Trading Activity

On October 10, 2025, Mercadolibre (MELI) closed with a 6.21% decline, marking its worst daily performance since [date]. The stock traded with a volume of 1.58 billion shares, a 35.42% increase from the prior day, ranking 74th in overall trading activity on U.S. exchanges. This sharp reversal came despite the company maintaining its position as a key player in Latin American e-commerce.

Analysts noted that the selloff aligned with broader market rotation away from growth sectors, though no company-specific catalysts were identified in the latest reporting period. Institutional selling pressure intensified in the latter half of the session as short-term traders reacted to mixed regional economic indicators. The volume surge suggests heightened conviction in the move, with liquidity drying up during the final hour of trading.

To run this back-test with professional accuracy I need to pin down a few practical details that aren’t yet specified: Market / universe — Which exchange(s) should be scanned each day to find the “top-500 volume” names? Entry & exit time-stamps — Do we assume we can buy the 500 stocks at the next day’s open and exit all of them at the close of that same day? Transaction costs & slippage — Should we include any per-trade commission or bid-ask slippage assumptions? Re-balancing mechanics — Equal-weighted across the 500 names each day, correct?