Why do many large companies use a Mastercard PCard and a seperate American Express card for T & E expenses?
I would like to know the reasoning behind large companies choosing to use a Mastercard (PCard, aka Procurement Card) for all general purchases and an American Express card for all travel and entertainment relation expenses. It doesn’t seem like the most cost effective option. Why not just use one corporate card for all transactions. Many companies use either method. Just curious as to why go with one over the other.

Your question provides the answer! A Master Card PCard is used by a business for making purchases (office supplies, maintenance products, general expenses, etc..) while the AMEX T&E card is used specifically for Travel and Expense items. AMEX has a long history of specializing in T&E expenses and has the systems in place to support this activity. Companies usually give their PCard business to Master card or Visa since these are accepted by MANY more places than AMEX is (which is accepted by most T&E type locations).