On Tuesday, CNN reported that corporate insiders have sold off an average of $600 million worth of stock every day in August.

This will likely mark the fifth month of the 2019 in which insider selling exceeds $10 billion — the first time this has happened since 2007, which preceded a severe financial crisis and recession.

This news comes amid continued warning signs that the economy is slowing down, with the yield curve inverting and markets behaving unstably.

The 2010s have seen one of the longest sustained economic expansions in American history following the financial crisis of 2008. But that expansion has occurred over a backdrop of rising income inequality and tepid wage growth that has left even gainfully employed people struggling to afford housing, health care, and higher education.

The GOP-backed corporate tax cut in 2017 led to a brief boom in corporate profits, but very little of it filtered down to workers, and the benefit to capital investment has proven temporary. Meanwhile, President Donald Trump’s increasingly aggressive tariffs on China and the European Union have driven up consumer prices and wounded the agricultural sector.

It remains unclear whether the U.S. will actually enter a recession within the next year. But investors appear to believe it’s a big enough risk that they are taking drastic action to protect their own finances.