Arm Shares Tumble 2.53% with 600M Volume Ranking 195th Amid Strategic Pact and EU Regulatory Concerns

On September 25, 2025, Arm Holdings (ARM) closed down 2.53% with a trading volume of $600 million, ranking 195th in market activity. The decline followed a strategic partnership announcement with a semiconductor manufacturer, which included long-term supply agreements but excluded equity stakes or governance changes. Analysts noted the muted reaction reflected market skepticism about near-term margin expansion potential despite the deal's scale.

Investor sentiment was further tempered by regulatory developments in the EU, where the European Commission finalized a revised antitrust framework for AI chipmakers. While the policy update did not directly target Arm, it introduced stricter compliance requirements for cross-border licensing agreements. Short-term traders focused on the stock's 14-day RSI dropping below 30, signaling potential oversold conditions ahead of earnings season.

To carry out this back-test we need to turn your idea into a precise, machine-executable specification. There are two practical details that still need to be pinned down: 1. Trading universe • “Top 500 stocks by daily trading volume” can be calculated within any universe (e.g., all U.S. common stocks, only S&P 500 constituents, HK-listed shares, etc.). • Please confirm which market/universe you would like to use. 2. Trade timing conventions • A 1-day holding period can be defined in several ways. The most common institutional convention is: – Rank yesterday’s trading volume. – Buy the chosen names at today’s open. – Liquidate them at tomorrow’s open (a full trading-day hold). • Alternatives (buy at today’s close, sell at tomorrow’s close; or open-to-close the same day) are also possible. If you’re happy for me to choose reasonable defaults, my recommendation would be: • Universe: all U.S. common stocks listed on NYSE, NASDAQ, or AMEX. • Trade timing: rank on prior day’s volume, buy at today’s open, sell at tomorrow’s open, equal-weighting the 500 names each day (no transaction-cost modelling). Please let me know if these defaults are acceptable or if you’d like any adjustments.