In theoretical economics, investment means buying (and therefore producing) capital goods - not being consumed but being used in future production. Examples include building railroads, or factories, cleaning the land, or allowing yourself to go to college. Strictly speaking, investment in formula GDP= C + I + G + NX is also part of gross domestic product. In that respect, the function of investment is divided into non-residential investments (such as factories, machinery, etc.) and residential investment (new homes). The correlation between I = (Y, I) is known to have a close relationship with income and interest rates. Higher incomes would boost higher investment, but higher interest rates would discourage investment because it would be more expensive to borrow. Even if companies choose to use their own funds to invest, interest rates represent the opportunity cost of investing in those funds rather than the interest that will lend out. 3. Remove the gasoline pump in the car Euroglaze trade customers are seeing returns on the company’s ongoing marketing investment, with leads generated now being distributed directly to them.