The full list of sub contractors is available in the DPA that our customers sign.
In short, however.
With one exception, all eMarketeer is stored and processed in the EU.
The exception is the feature FullContact which, if used, queries a server in the US using email addresses.
FullContact.com operates in compliance with the EU-US Privacy Shield, but as admin in eMarketeer this service can be disabled.
The option to disable FullContact is available under Account -> Plugins and Integrations in eMarketeer.