With 260 million consumers and a GDP of over $3 trillion, Mercosur is the world's fourth-largest trading bloc and Canada has been in exploratory talks with the quartet to join the free trade deal.
National University of Singapore economist Davin Chor said the deal showed that the rest of the world was prepared to advance free trade, with or without the US.
The U.S. wasn't the only signatory to have its fair share of skeptics.
Still another fear was recently voiced in New Zealand: Perhaps the US will return to the agreement.
According to the Ministry of Foreign Affairs and Trade's estimates, the deal is expected to give a $1.2 billion to $4b boost to New Zealand's real gross domestic product.
"The signing of the Agreement enables us to move to the next phase".
On Thursday, Munoz said CPTPP was not an agreement against anyone and several governments had said they want to join it.
As to how likely that prospect may be, well, it's tougher to say than one might expect.
The CPTPP agreement leaves the door open for the United States to rejoin the club, a step Mr Trump in January hinted he would be open to if the U.S. could get a "substantially better deal". That sentiment was echoed just last month by Treasury Secretary Steven Mnuchin, who reportedly told an investment summit he has begun to "have very high-level conversations" about the agreement, which "is something the president will consider".
Washington's exit meant a drastic downsizing of the original agreement - which with United States involvement represented 40 per cent of the global economy.
"The value of the TPP 11 is reinforced by the United States tariff decision".
Coming in the same week that Trump risked a trade war over his decision to introduce tariffs on imported steel and aluminum, the deal is seen by some members as striking a blow against protectionism.
As well, Trump has threatened to kill the North American Free Trade Agreement renegotiations that are underway with Canada and Mexico.
Dozens of people protested on Wednesday in Chile where the signing of the new Trans-Pacific Partnership Agreement (TPP) will take place in the country's capital.
The TTP-11, as the treaty is also known, has several detractors within civil society, but experts and government from all signing countries agree that it is one of the most audacious and beneficial deals reached in the world.
The TPP was a key policy of the former Obama administration's so-called foreign policy pivot to Asia.