The clock is ticking on the R&D tax credit, and businesses have no way of knowing if it will be renewed. The perpetual uncertainty around the credit is pushing some companies to shift research overseas and making it harder for smaller firms to compete with larger rivals, writes Emily Chasan in today’s Marketplace section. Lawmakers “play chicken with it,” says Dell CFO Brian Gladden. “What companies do is they make decisions based on an assumption that it’s not going to happen.”