Amazon announced Thursday that it has opened a search for a second U.S. headquarters, where it will expand to 50,000 employees and invest $5 billion in construction and operations.

Why it matters: This announcement is a way for the company to show the benefits of its bigness: it has the means to spur major economic development in a state that needs it. Expect Amazon to look for potential headquarter cities in the Midwest and Rust Belt that have fallen on hard times.

Why now: Amazon is growing fast, which is starting to worry some policy makers about the disproportionate control the company increasingly has on a number of markets and what that means for mainstay retail operations in American communities (i.e. grocery stores). Meanwhile, many cities in the U.S. are struggling with the fall of mid-western manufacturing jobs and the concentration of high-paying tech jobs on the west coast.