The phrase "red arrow" usually refers to a symbol that looks like a direction arrow colored in red. It can represent a downward movement or decrease in value, often used in stock markets or traffic signs. Full definition
The orange and red arrows show the strongest winds that make up the jet stream. (sciencedaily.com)
It marks bullish patterns with a green arrows and bearish patterns with red arrows. (tradingsetupsreview.com)
I know I'm going to get dozens of red arrows, but it's something I've thought for a while now, and his recent behaviour has convinced me I'm right. (justarsenal.com)