Be in the red and Fall behind

Fall behind and be in the red are semantically related In some cases you can replace term "Fall behind" with "Be in the red", this terms are similar.

Fall behind verb - Hang (back) or fall (behind) in movement, progress, development, etc..

Be in the red and fall behind are semantically related in get into debt topic. Sometimes you can replace phrase "Be in the red" with "Fall behind", this terms are similar.