After so many complaints that the 17 Sustainable Development Goals, SDGs and its 169 targets are unwieldly and unlikely to be effective (see for instance The 169 commandments: The proposed sustainable development goals would be worse than useless at The Economist) it seems preposterous to suggest that another Goal may be needed. But yes, there is a glaring omission in those goals and targets.
Even though the bulk of the proposed actions rest with the public sector, it is recognized that governments alone cannot achieve the goals. Expectations are very high that the private sector will contribute to their achievement. In fact many enlightened companies and private sector organizations have already started with efforts to contribute, some by imputing activities that they have already been carrying out to the achievement of the SDGs (nice marketing tool!) and also by developing programs to enhance those contributions in the future. But this underestimates the power of the private sector to contribute to sustainable economic development.
Current SDGs have the underlying expectation that the private sector will make a contribution, but there are no details as to how or what governments would need to do to make it effective.
Nowhere in the 17 SDGs and 169 targets is there any hint as to how the private sector will be able to contribute. It is as if it is supposed to occur automatically. In fact the word “enterprise” is mentioned only twice, in the context of facilitating access to finance to SMEs and the word “companies” is mentioned only once, in Target 12.6: “Encourage companies, especially large and transnational companies, to adopt sustainable practices and to integrate sustainability information into their reporting cycle”. Will this “encouragement” really rally the private sector to contribute the achievement of the goals?
Sustainable and responsible economic growth of business are critical for the creation of employment and other human development opportunities, which is the best antidote for poverty reduction, enhancing the self-esteem and dignity of the person and contributing to social stability. This will probably be the most notable contribution that the private sector can be to the SDGs, besides specific, pointed contributions to some other goals based on the comparative advantages of specific industries like agriculture, foodstuffs, energy (emissions reduction), financial services (SME finance), pharmaceuticals, etc.
To effectively contribute to the SDGs the private sector needs to be able to carry out their activities efficiently and effectively for which they need clear and stable rules of the game, which are the responsibility of governments. They need a conducive business climate.
A proposal: An 18th Goal
While we have not discussed all aspects of the business climate in order to keep this article simple, the following proposal is based on such an analysis and will, hopefully, be self-explanatory. 
Goal 18: Promote the development of a business climate conducive to the conduct of business by the private sector so they can contribute to the achievement of the previous 17 Goals.
Target 18.1: Remove obstacles for the creation, operation and closing of business in accordance to international best practices in labor, domestic and international commerce, investments and property rights issues and promote the development of a supporting ecosystem for SMEs
Target 18.2: Strengthen business regulatory institutions to enhance their efficiency and effectiveness, considering the cost and benefits of regulations.
Target 18.3: Strengthen the judicial system and alternative processes for dispute resolution so that business have access to impartial justice, efficient in term of costs and time and effective in terms of case resolution.
Target 18.4: Prepare and implement national plans to guarantee protection, respect and remediation of Human Rights by governments and businesses, in particular upgrading legislation and regulations to international best practices.
Target 18.5: Revise criminal codes to establish personal responsibilities for crimes committed by individuals when carrying activities on behalf of businesses.
Target 18.6: Coordinate legal frameworks between countries in order to eliminate tax evasion, in particular on issues related to location of revenues and expenses, financial transaction between related businesses and transfers prices for goods and services.
Note that the targets are balanced, they ask for a better climate but also include measures to strengthen the control instruments and the administration of justice to ensure responsible behavior. There is no assumption that companies are all well-behaved and responsible.
If the reader thinks the language is generic, it is because it uses the same style as the other goals and targets. Are Goal 18 and its 6 targets utopian? They are as equally utopian as the previous 17 Goals and 169 targets.
And this would have the collateral benefit of having 18 Goals and 175 targets which are more attractive numbers than the current 17 and 169.
A more comprehensive version of this article appears in Spanish in the author´s blog www.cumpetere.blogspot.com
 A good reference for a comprehensive analysis of the business climate in most countries of the world is the World Bank annual publication on Doing Business.