Inexpert company invested in rude slow server option? (9)

I haven't cracked this one yet — but the brilliant team at Fifteensquared have:

LAY (non-professional = inexpert) + CO (abbreviation for company), inserted into CURT (speaking abruptly in a way considered to be rude). A type of tennis court (where players serve), considered “slow” because balls lose more of their initial speed when striking the surface than on other types of court.