IonQ and Worthington Enterprises led premarket gainers, with IonQ jumping 12% after announcing what it described as the industry's first real-time quantum error decoder. The capability enables quantum error correction during operations without slowing execution, the company said. IonQ's move lifted the broader quantum sector, with Rigetti Computing, D-Wave Quantum and Infleqtion each rising more than 5.5%. Worthington surged about 16% after CEO Joseph Hayek cited opportunities across the business, including growing demand for engineered American Society of Mechanical Engineers tanks used in data-center liquid-cooling systems. Its first-quarter adjusted earnings and revenue exceeded LSEG estimates. KB Home fell more than 1% after its fourth-quarter delivery outlook missed expectations, while projected current-quarter housing gross margins of 16% to 16.6% trailed analysts' 17.2% estimate. Six Flags Entertainment gained 1% following a Wall Street Journal report that Jana Partners was urging the company to consider a sale after disappointment with its second-quarter earnings. Maplebear, the owner of Instacart, climbed more than 3% after saying customers could use Meta's personal AI agent Muse on its grocery platform, adding to partnerships with OpenAI's ChatGPT, Anthropic's Claude and Google's Gemini.