Why the stock markets are tanking

Tariffs: President Trump's expected announcement of anti-China tariffs, which have taken a particular bite out of Dow components like Boeing and Caterpillar. Stocks rebounded slightly after news came that the tariffs would not be imposed until after a 3o-day public comment period, which could let U.S. businesses plead their case. But then they resumed their plummet.

Financials: The LIBOR rates, which are the interest rates at which banks lend to one another, have hit their highest levels since 2008, thus hammering bank stocks.

Tech-lash: Facebook shares continue to fall, amid calls for increased regulation that could impact broader social media ad models. Some tech hardware companies, like Apple, also are experiencing tariff-related drops.