Scenario 1: Individual Retirement Accounts (IRAs) allow people to shelter some of their income from taxation. Suppose the maximum annual contribution to such accounts is $5,000 per person. Now suppose there is an increase in the maximum contribution, from $5,000 to $8,000 per year. Shift the appropriate curve on the graph to reflect this change. This change in the tax treatment of saving causes the equilibrium interest rate in the market for loanable funds to and the level of investment spending to Scenario 2: An investment tax credit effectively lowers the tax bill of any firm that purchases new capital in the relevant time period. Suppose the government repeals a previously existing investment tax credit. Shift the appropriate curve on the graph to reflect this change. The repeal of the previously existing tax credit causes the interest rate to and the level of investment to Scenario 3: Initially, the government's budget is balanced; then the government significantly increases spending on national defense without changing taxes, This change in spending causes the government to run a budget, Shift the appropriate curve on the graph to reflect this change This causes the interest rate to which the level of investment spending national saving.