'Do' and 'does' are equally forms with the existing indefinite tense in the verb 'to perform.' Which one particular you can expect to use will typically depend upon the sentence's issue. Their utilization is almost identical, apart from just one instance where you can use 'do' and not 'does.' https://financefeeds.com/citibank-sued-over-20m-romance-scam-that-funneled-millions-through-its-accounts/