Fixed capital was originally a form of production capital, but it used to refer to some durable goods in non-production fields, such as houses, school buildings, government agencies, cinemas and so on. As unproductive fixed funds, they perform the same function, because those things are also used for a long time and keep their original material form.

The sources of fixed funds are:

① National fixed fund

It consists of fixed funds directly invested by finance or increased taxes payable, return of investment loan profits and free transfer of fixed assets;

② enterprise fixed fund

Refers to the self-raised funds of enterprises, including the fixed funds formed by purchasing and building fixed assets with profit retention and depreciation funds and returning investment loans.

Liquidity refers to all current assets of an enterprise, including cash, inventory (materials, products in process and finished products), accounts receivable, securities, prepayments and other items. All the above items are necessary for business operation, so working capital has a popular name, called working capital. Liquidity in a narrow sense = current assets-current liabilities.

Liquidity = current assets-current liabilities, in which:

Current assets = accounts receivable+prepayments+inventory+cash

Current liabilities = accounts payable+accounts received in advance

Liquidity investment (advances) in a certain year = liquidity demand this year-liquidity investment as of last year or = liquidity demand this year-liquidity demand last year.