Pinterest Stock Plunges 4.61% on October 10 as $290M Volume Ranks 443rd in Market Activity

Pinterest (PINS) closed 4.61% lower on October 10, 2025, with a trading volume of $290 million, ranking 443rd in market activity for the day. The decline came amid mixed investor sentiment toward the social media platform’s recent strategic updates and broader market dynamics.

Analysts noted that the stock’s performance was influenced by evolving user engagement metrics and competitive pressures in the advertising sector. While the company has emphasized long-term growth initiatives, short-term volatility remains tied to macroeconomic factors affecting digital advertising spending. Institutional investors have shown cautious positioning, with some hedging against sector-wide headwinds.

To run this back-test accurately I’ll need to pin down a few practical details that weren’t specified: 1. Market universe • Should we limit the stock pool to a specific exchange (e.g., all primary-listed US stocks on NYSE + NASDAQ), or do you have another universe in mind? 2. Weighting & capital allocation • Equal-weight across the 500 names each day, or a volume-weighted (or value-weighted) allocation? • Any cash buffer you’d like to keep idle? 3. Frictional costs • Do you want to include estimated transaction costs (e.g., 2 bp per trade each way) or assume zero slippage/commission? 4. Risk-control overlays • Stop-loss, take-profit limits, or maximum drawdown rules to enforce? (If none, we’ll run it “raw.”) 5. Price series • Use daily close prices for entry/exit, or open-next-day open prices, etc.? 6. Data frequency • Daily rebalancing (buy today’s top-volume list at today’s close, exit at tomorrow’s close) is my current interpretation—please confirm.