> The discrepancy between international and domestic migration in the Bay Area can likely be explained by what economists call "gateway cities." These cities, often planted along the coast, serve as entry points for foreigners moving to the U.S. The immigrants will register in the gateway city, but often move to other parts of California or the country within months, according to Phuong Nguyen, a research specialist at the California Department of Finance.

And while it might be statistically "insignificant" in the absolute, you have to look at how it compares to other cities to really understand how healthy that number is. A contrast: the net domestic migration of Sacramento County was +15,224. -2500 looks far less healthy next to that.