Are purchase transactions made through a company card that allows buying goods on credit, with an additional amount specified in case of late payment, considered to have usurious interest, or is the payment limited to the market price of the good?

It is not permissible to use a credit card that imposes a penalty for late payment, because this penalty is forbidden usury (riba). Any stipulated increase on a debt is usury, whether the debt is a loan or the price of a sold item. The Fiqh Council has explicitly stated the impermissibility of obligating the debtor to an increase on the debt due to delay, and has forbidden the issuance of uncovered credit cards if they stipulate a usurious increase. Sheikh Ibn Uthaymeen issued a fatwa (definition) prohibiting this transaction because the person dealing with it commits to giving usury upon late payment.