grammar - Can't decide whether to use focus or focuses in this sentence

I feel like I should use "focuses" as using "focus" sounds weird in the following sentence.

Risks are not identified prospectively, i.e. this is a case of “Fighting the Last Battle” syndrome, whereby management focus most on risks that have occurred recently.

Are they both acceptable? I'm not big on the rules of the English language, I tend to just go by what sounds right in my head and here "focus" seems out of place.

I appreciate any feedback.