How are money-transfer companies impacted by volatility and intermarket rate movements, and do these changes affect their FX markups?

From a cross-border money transfer point of view, the volatility is gripped at the very moment the transaction is executed, i.e. the booking is done, so regardless where the market is (price-wise), once a transaction is booked, there is very little exposure for the remitter/sender. Intermediaries, depending on their spread on FX, could win/lose on each transaction, but this has been their cornerstone for many years. Extremely volatile markets have larger spreads, and more stable markets, have a narrow spread gap.

It definitely affects mark-ups, but one must also be cognizant that markups also factor competition into their equation. More competition, yields a lower mark-up and hence the exposure to volatility can go south. The key is the quick settlement of the trade on both ends, before the volatility goes against you.