This one sign could indicate that a stock-market sell-off is near, Wells Fargo trader says

· *Chris Harvey, Wells Fargo Securities head of equity strategy, told CNBC that short interest ticking up from low levels could indicate stock market sell-offs. *
· *"It's not a catalyst by itself, but it's a concern, and it's a concern as we see the market melting up," he said.*
· *Short interest on the S&P 500 as a...