The U.S. stock market saw some dramatic moves past week with five stocks posting the largest weekly gains and drops (Mon-Fri Sept 29-Oct 3, 2025). For each, we highlight the drivers of the move and year-to-date (YTD) performance.

To track momentum in real time, you can use FMP's Top Traded Stocks API to see the most actively traded names. With your FMP API key, the Investor Dashboard provides a comprehensive view with deeper context - insider trades, stock price targets, revenue segmentation, and EPS trends.

Top 5 Gainers/Losers

Western Digital (WDC) — Top Gainer (~+13% this week)

A wave of bullish analyst calls (Morgan Stanley nearly doubled its PT to $171) and a stronger AI/cloud storage demand narrative sent shares surging. YTD: ~+180% into Oct 3.

Bio-Techne (TECH) — Gainer (~+22% this week)

Momentum followed fresh product advances in spatial biology (RNAscope & Lunaphore COMET) highlighted at late-September industry events. YTD: ~-12% into Oct 3.

Coinbase (COIN) — Gainer (~+20% this week)

Crypto rallied as Bitcoin reclaimed $120k, lifting crypto-exposed equities; COIN also benefited from a fresh broker upgrade. YTD: ~+47% into Oct 3.

Wynn Resorts (WYNN) — Loser (~-4% this week)

Macau-exposed casinos slid after China Golden Week travel data disappointed; WYNN logged the S&P 500's sharpest single-day drop on Friday. YTD: ~+48% into Oct 3.

Las Vegas Sands (LVS) — Loser (~-6% this week)

Same Macau/Golden Week softness pressured sector peers; LVS was among the S&P's biggest decliners Friday. YTD:low-single-digits to mid-single-digits positive into Oct 3.

Track Market Liquidity in Real Time with FMP's Top Traded Stocks API

The Top Traded Stocks API shows which tickers are commanding the most attention right now—a handy complement to weekly performance:

• Most Active Lists: Instantly see the highest-volume stocks across major U.S. exchanges (or filter by NASDAQ/NYSE).
• Real-Time Volume + Price Metrics: Monitor volume, price change, and % change to gauge momentum and liquidity.
• Company Snapshot: Pull names, symbols, and trading volume for quick context.

Example use case: A day trader scans NASDAQ via the Top Traded Stocks API and spots iSun (ISUN) printing unusually high volume. With real-time volume and price-change data in hand, they can decide whether the momentum fits their setup before entering a trade.