Dow falls 500 points and tech stocks slide

By John Towfighi, CNN New York (CNN) — US stocks tumbled Thursday as concerns mounted about expensive tech stocks and a risk-off sentiment spread through markets after new data showed a bleak outlook for the job market. The Dow was down 507 points, or 1.07%. The broader S&P 500 fell 1.16%. The tech-heavy Nasdaq Composite