It is an economic theory created by John Elkington in 1994. It is also called TBL or 3BL. In economic parameters, it is an accounting system that argues that companies should be focused on social and environmental problems and profit-oriented.
According to traditional business accounting, the bottom line of the income and expense statement is profit or loss. Two more underscores are added with the triple underscore theory. According to the idea, social and environmental (ecological) concerns are added as lines, just like profit and loss. As of 2007, it has been accepted that TBL Standards should be applied to United Nations urban and community accounting.
The United Nations has been created with different standards to assist with the measurements required by the TBL. It has been discussed that it should be changed to four lower lines in order to distinguish sustainable development and sustainability concerns from previous social, environmental, and economic considerations. With the fourth bottom line, it is argued that a future-oriented approach should be adopted. It is argued that important concepts such as equality between future generations should be addressed. In the private sector, businesses that undertake corporate social responsibility projects related to the environment and people are under the obligation to report to the public. The level of commitment of companies to corporate social responsibility projects and the impact of their projects on the environment and society over time is measured by the TBL system.