SCHW leads premarket movers after earnings beat.

Charles Schwab beats earnings expectations, while Alphabet's stock drops after reports that Samsung may replace Google with Microsoft's Bing as the default search engine on its devices. M&T Bank's stock jumps after posting better-than-expected quarterly figures, while State Street's stock falls more than 10% after posting lower-than-expected earnings. HP's stock rises after JPMorgan upgrades the computer builder to overweight from neutral, while Dell's stock drops after being downgraded to neutral from overweight. Merck acquires Prometheus Biosciences for $10.8 billion, causing shares of Prometheus to rally 69%.