The "Big 4" in the beef industry are JBS, Tyson Foods, Cargill, and National Beef, which are some of the largest meatpacking and processing companies in the world. These companies have significant economic power and influence in the beef industry due to their large market share and control over the supply chain. They are able to exert significant influence over the prices paid to farmers and ranchers for their livestock, and have significant power to set industry standards and practices.

In terms of political power, these companies have significant lobbying presence in the United States and other countries in which they operate. They often have direct access to government officials and regulators and are able to influence the development and implementation of laws and regulations that affect the beef industry. They also have significant influence over trade policies and negotiations, particularly with regard to exports of beef to other countries.

It's worth noting that due to their size and power, these companies have been subject to regulatory oversight and anti-trust investigations in some countries, particularly in the US. Some of their practices have been criticized for leading to a consolidation of the industry, which could lead to a lack of competition and a reduction of the bargaining power of farmers and ranchers.