The Japanese language actually does have an idiom for "in the red". It's written as 赤字, which literally means "red letter" or "red text". The opposite is 黒字, or "black letter" / "black text" which is equivalent to English's "in the black".
I guess this just doesn't carry over into the charts used in the financial sector?
I guess this just doesn't carry over into the charts used in the financial sector?