Mastercard has published its global tax principles on its main US site.  These can be accessed here

Our global tax principles are based on our approach to tax governance, the management of tax risks, tax compliance and reporting, and our relationship with tax authorities. We recognize that tax is an important element of our overall corporate social responsibility. These global tax principles apply to all Mastercard entities and majority-owned Mastercard affiliates. Newly acquired affiliates must conform their policies (or adopt this policy) no later than the first anniversary of the closing date of such acquisition.

The Global Tax Principles as well as the referenced tax policies are reviewed and approved by the Chief Financial Officer and the Executive Vice President, Tax.

Our UK Tax Strategy is in line with our Global Tax Principles but has some additional local processes and procedures.