When the government taxes corporations (big or small), it is taking money that the corporations could have used to purchase labor, services, raw materials, finished products, etc. The government then uses the taxes it collects, spends a majority on itself to keep the lights running, and pays all the people it needs to confiscate corporate earnings. With the pittance remaining, it buys labor, services, raw materials, finished products, etc. The difference is it buys much, much less than private corporations could have bought if tax rates had not risen.
Big government "stimulus" programs work much less effectively and much less efficiently than corporate investments. They create a net loss of funds available to invest in the economy.