SafeCo, a country Z corporation, has sales subsidiaries throughout Europe and Asia. SafeCo sells in the United States through its employee, Tom Johnson, who works out of his home but meets with sales prospects daily. Pre$-$tax income attributable to Tom$$s sales constitute $$1$ million.

a$.$ Does SafeCo have a U$.$S$.$ trade or business? Why or why not?

b$.$ If country Z has a treaty with the United States similar to the Model Treaty, would SafeCo have a permanent establishment in the United States? Why or why not?