The United States of America is being the top country by gross capital formation in the world. As of 2015, gross capital formation in the United States of America was 3,184,503 million volume, at constant 2005 prices - US dollars that accounts for 20.89 % of the world's gross capital formation. The top 5 countries (others are China, Japan, India, and Germany) account for 54.56 % of it. The world's total gross capital formation was estimated at 15,240,913 million volume, at constant 2005 prices - US dollars in 2015.
Gross capital formation (also known as gross domestic investment) consists of outlays on additions to the fixed assets of the economy plus net changes in the level of inventories. Fixed assets include land improvements (fences, ditches, drains, and so on); plant, machinery, and equipment purchases; and the construction of roads, railways, and the like, including schools, offices, hospitals, private residential dwellings, and commercial and industrial buildings. Inventories are stocks of goods held by firms to meet temporary or unexpected fluctuations in production or sales, and 'work in progress'. According to the 1993 SNA, net acquisitions of valuables are also considered capital formation.