There doesn't seem to be much information publicly available regarding how payment networks manage transactional FX risk exposure, but I did find this:
MasterCard enters into transactions in derivative financial instruments, typically in the form of foreign currency forward contracts, to manage risk associated with anticipated receipts and disbursements which are either transacted in a non-functional currency or valued based on a currency other than its functional currencies. MasterCard also enters into foreign currency forward contracts to offset possible changes in value of assets and liabilities denominated in foreign currencies due to foreign exchange rate fluctuations. MasterCard does not engage in proprietary trading of derivatives. Its objective for entering into transactions in derivative financial instruments is to reduce exposure to transaction gains and losses resulting from fluctuations of foreign currencies against its functional currencies. MasterCard engages in derivatives transactions solely and exclusively for the purpose of hedging foreign currency exchange risk incurred in the operation of its business.
As noted above, MasterCard has approximately 20,000 customers, and processes payment card transactions from more than 210 countries and territories. MasterCard derives approximately 60% of its revenue from outside of the United States. Given the global reach of our company, we are deeply impacted by fluctuations in foreign currency exchange rates in the operation of our business. MasterCard generates revenues and incurs expenses that are either transacted in, or valued based on, currencies other than the U.S. Dollar. For example, MasterCard charges its customers assessment fees for various services it provides to its customers, including the use of the MasterCard brand globally. These assessment fees are typically a percentage charge on a customer's total volume of transactions incurred on MasterCard-branded cards. Because of MasterCard's global presence, transactions effected in foreign currencies are converted into U.S. Dollars and the percentage charge (i.e., assessment fee) is calculated on this converted U.S. Dollar volume. Hence, fluctuations in foreign exchange rates impact the amount of U.S. Dollar assessment revenue MasterCard collects. Similarly, given our global footprint, we make significant expenditures and incur significant contractual obligations to make future expenditures in countries around the world for commercial activities, such as marketing, advertising, payroll and operations. These expenditures and obligations may be denominated in currencies other than the U.S. Dollar. This exposes MasterCard to fluctuations in foreign exchange rates. In addition to our transactional exposures, we also hedge balance sheet assets and liabilities denominated in foreign currencies. From time to time, MasterCard is also exposed to foreign exchange risks arising from overseas acquisitions.
Source: https://www.fdic.gov/regulations/laws/federal/2011/11c89ad79...