Nike warned that its turnaround is taking longer than it expected, leading three Wall Street banks to downgrade the stock as investors lose patience.

It's hard for the market to have faith in Nike when its guidance continues to fall short of expectations.

Nike warned that its turnaround is taking longer than it expected, leading three Wall Street banks to downgrade the stock as investors lose patience.

Nike issued Tuesday a weak sales forecast, sparking a sell-off of its shares.