Final answer:
An increase in household saving increases the supply of loanable funds, while open market sales by the central bank, increased government spending, and increased investment demand do not directly lead to an increase in the supply of loanable funds.
Step-by-step explanation:
The supply of loanable funds in the financial market can be increased by certain actions. Generally, an increase in household saving leads to more funds being available for banks to lend out, which directly increases the supply of loanable funds. Contrastingly, open market sales by the central bank, which typically aim to reduce the money supply, do not increase the supply of loanable funds. Also, an increase in government spending without a corresponding increase in revenue can reduce the supply of loanable funds by leading to higher deficit financing. Increases in transfer payments do not directly affect the supply of loanable funds, unless they lead to increased saving. Finally, an increase in investment demand would generally lead to a rise in interest rates rather than an increase in the supply of loanable funds; it reflects a desire to borrow rather than to lend.