Learn Spanish (Latin America): Capaz que aumentan las ventas.

Even though capaz que expresses possibility, it is very commonly followed by the indicative mood in everyday Latin American Spanish. Using the indicative (aumentan) implies the speaker feels this is a very real, likely possibility. You can also use the subjunctive (aumenten), which just makes the increase sound slightly more doubtful or hypothetical.

I learned that capaz means capable. How does it mean might here?

While capaz does mean capable when describing a person's abilities, the set phrase capaz que is used heavily in informal Latin American Spanish to mean maybe, perhaps, or it's possible. It functions a lot like a lo mejor.

Why does the verb come before the subject (las ventas)?

In Spanish, it is very natural to place the subject after the verb when introducing new information or when using verbs that describe things happening, changing, or existing. You could completely safely say Capaz que las ventas aumentan, but the verb-first order flows perfectly in conversational Spanish.

Is capaz que appropriate to use in a formal business context?