。
I run a business on a large scale.
Literal
I [topic-は] business [object-を] large-scale-[manner-に] am-running.
営む (いとなむ, 'to run/manage a business') is a somewhat literary verb for business operations. 大規模に — the な-adjective 大規模 in adverbial に form. ~ている marks the ongoing state.