The largest sector of the macroeconomy is the government. The other sectors of the macroeconomy include the household sector, the business sector and the foreign sector.
The government sector of the macroeconomy is so large because it encompasses all of the nation's governments at the federal, state and local levels. This includes all government agencies, the military, public school systems throughout the country and a countless number of publicly funded projects. All sectors of the macroeconomy are quite substantial and play an important role in the national economy, but the government sector is certainly the largest division of the four sectors.