Still, big gaps remain in the crisis response capabilities — which is why events in Greece and Spain this spring have galvanized most European leaders to seek longer-term solutions to the currency union’s acknowledged shortcomings. The euro zone, for instance, lacks a Europe-wide deposit insurance fund, which would be a crucial tool if an emergency in Greece provoked bank runs in other countries.

Corporate money has largely fled Greece and has been flowing out of Spain. Without a European equivalent to the Federal Deposit Insurance Corporation in the United States, it is unclear how authorities on the Continent would reassure ordinary depositors that their money was safe enough to prevent a rush for the exits.

“That could be the danger,” said Peter Westaway, chief economist for Europe at Vanguard Asset Management in London. “If it gets out of control so quickly, how do you stop that?”

Many companies have been preparing for a European shock at least since the end of last year.