Shift4 operates in European retail with Global Blue, the Swiss payments technology firm it acquired last year for $2.5 billion, including $1 billion in debt. The Middle East and southeast Asia are significant sources of travel customers for Global Blue’s tax-free shopping business, which represents about 20% of Shift4 revenues. Shift4 remains “incredibly happy” with the Global Blue acquisition, Shift4 CEO Taylor Lauber said Friday in an interview. The company expects a $25 million impact to its tax-free shopping business in the third quarter, along with a $20 million drag expected from currency exchange. Shift4 expects to add “thousands of merchants per month in the near future,” through Global Blue, Lauber told analysts Thursday on the company’s earnings call.