This year Americans are jostling with the Chinese for top spot among overseas investors lured by Portugal's "golden visas" -- residents permits issued for foreigners prepared to buy property or transfer capital to the Iberian country.

"They really want to come and live here and adopt a different lifestyle," she said, even though the introduction of the golden visa scheme in 2012 has contributed to an unwelcome surge in property prices.

In Lisbon, Hadlock runs get-togethers to develop business ties between California and Portugal. The group calls itself Red Bridge, in a nod to the red suspension bridges spanning San Francisco Bay and the Tagus estuary.