"If elected, he poses a unique danger to the functioning of democratic and economic institutions, and to the prosperity of the country. For these reasons, we strongly recommend that you do not vote for Donald Trump."
Despite the opposition to Trump, economists are also against Hillary Clinton's policies. In September more than 300 economists published a letter addressing Clinton's "ill-advised economic agenda."
Trump's odds at a win are narrowing and markets are bracing for Brexit 2.0.
As the Republican nominee pulls even with Clinton in the polls following the FBI's email probe bombshell, financial markets around the world are seeing heavy selling.
The Vix index - commonly referred to as Wall Street's "fear gauge", which measures expectations of stock market volatility, has risen to its highest level since the UK's Brexit vote, the Financial Times reported.
Meanwhile, gold spiked overnight, and the Mexican peso plunged.