International investment agreements (IIAs) have been at the center of international economic law for decades. These agreements are bilateral or multilateral treaties that regulate the conditions under which investments are made and protected between states and investors. Since the 1960s, the trend of concluding these agreements has dramatically increased, and today, there are more than 3,000 IIAs in place.

It all started with the Bilateral Investment Treaty (BIT), which was signed by Germany and Pakistan in 1959. This treaty established the principles of fair and equitable treatment and non-discrimination, which became the cornerstones of IIAs. The BIT was a model for other countries, and by the early 1980s, dozens of BITs had been adopted, primarily by developed countries.

In the 1990s, the number of IIAs increased dramatically, and the scope of these agreements became broader. Multilateral agreements like the North American Free Trade Agreement (NAFTA) and the Energy Charter Treaty (ECT) expanded the coverage of IIAs to include not only investment protection but also investment promotion and liberalization.

By the early 2000s, IIAs had become a standard feature of the international economic landscape, and their reach extended to almost every corner of the world. However, the emergence of new challenges in the global economy, such as the financial crisis of 2008 and growing concerns about climate change, exposed weaknesses in the existing IIA framework. Criticisms of IIAs range from concerns about their impact on public policy to their perceived bias in favor of investors and the threat they pose to national sovereignty.

In recent years, there has been a pushback against IIAs, with some countries terminating existing agreements or refusing to sign new ones. As a result, the number of new IIAs being concluded has slowed down. In response to these criticisms, some countries have begun to revise their IIAs to incorporate provisions that address the gaps in the existing framework.

In conclusion, the history of IIAs is a story of exponential growth over the past several decades, as more countries recognized the need to create a framework for investment protection and promotion. However, as the challenges of the global economy have evolved, the need for a more balanced and updated framework has become apparent. As we move toward the future, the debate over IIAs will continue, and their role in shaping the global economy will undoubtedly be further scrutinized.