Investors sold off major benchmarks on Tuesday after President Trump ratcheted up trade tensions, threatening new tariffs on more countries and implying that an agreement with China may take longer than the market is currently expecting. TheDow Jones Industrial Average (DJINDICES:^DJI)and theS&P 500 (SNPINDEX:^GSPC)were in the red all day but did close near highs of the session.

Data source: Yahoo! Finance.

As for individual stocks, Amazon.com (NASDAQ:AMZN) reported strong Cyber Monday sales, and Cleveland-Cliffs (NYSE:CLF) announced a merger agreement with AK Steel (NYSE:AKS).

Image source: Getty Images.

Shoppers opened their wallets on Cyber Monday, with online spending hitting forecasts for a new record and Amazon reporting the biggest shopping day in the company's history. Shares of the e-commerce giant slipped 0.7%.

Accordingto AdobeAnalytics, U.S. consumers spent $9.4 billion shopping online on Cyber Monday, up 19.7% from last year and matching the company's forecast, with results boosted by a burst of activity from late-night shoppers.

Amazonsaid that Cyber Monday broke the record for the number of items ordered worldwide on its platform and that customers ordered "hundreds of millions of products" in the days between Thanksgiving and Cyber Monday. Last year, the company reported sales of 180 million items during that period. Top-selling categories were toys, home, fashion and health, and personal care.

Retail stocks slumped despite the strong sales news, with the SPDR S&P Retail ETFfalling 1.4%. Worries that the next round of tariffs on Chinese goods -- which would hit retailers particularly hard -- may go into effect on Dec. 15 after all likely outweighed any optimism about the health of the U.S. consumer.

Ironore mining company Cleveland-Cliffs announced an agreement to acquire steel producer AK Steel in an all-stock deal, but investors gave the news a cold reception, with Cleveland-Cliffs shares tumbling 10.7% to $7.51 and those of AK Steel rising 4.2% to $3.01.

Under the terms of agreement, Cleveland-Cliffs will exchange 0.4 shares of its stock for each share of AK Steel, a price that had represented a premium of 16% as of the stock prices yesterday, but that has been mostly wiped out today.

The combination would create an integrated steel producer that the companies think will be more efficient and less exposed to volatile commodity prices. Cleveland-Cliffs believes that the merged entity will find $120 million in annual cost savings, and that lower risk resulting from vertical integration will allow it to pursue new growth opportunities.

Investors weren't convinced of the benefits, though, and the market capitalization of the two companies together fell 5% today.

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