By increasing the amount of money in the economy, the central bank encourages private consumption. Increasing the money supply also decreases the interest rate, which encourages lending and investment. The increase in consumption and investment leads to a higher aggregate demand.

What increases the money supply?

The Fed can increase the money supply by lowering the reserve requirements for banks, which allows them to lend more money. Conversely, by raising the banks' reserve requirements, the Fed can decrease the size of the money supply.

What happens if money supply increases?

Inflation can happen if the money supply grows faster than the economic output under otherwise normal economic circumstances. Inflation, or the rate at which the average price of goods or services increases over time, can also be affected by factors beyond the money supply.