No. If marginal cost of production decreases but market output stays the same, economic surplus and deadweight loss both increase, causing economic efficiency to decrease.

Anders Danielson has written:

'The economic surplus' -- subject(s): Economic conditions, Economic development, Surplus (Economics)

'The political economy of development finance' -- subject(s): Economic policy, Fiscal policy

Finance is the process of transferring fund from surplus economic unit to deficit economic unit. Domestic finance is the process of transferring fund from surplus economic unit to deficit economic unit within a country. And International finance is the process of transferring fund from surplus economic unit to deficit economic unit when any of these units is located outside a national country.

Economic surplus is necessary for development because it means a economy is producing more than its consuming. So it is exporting and making money and getting richer which leads to development.

An economic unit having access of funds and wants to lend his funds