1. Global market overview

Global stock markets have been rallying for weeks but now look rather soft.

U.S. stock futures are holding steady.

European markets are mostly dipping in early trading. Asian markets ended the day with mixed results.

This comes after the Nasdaq hit an all-time high on Monday, while the Dow Jones industrial average and S&P 500 each slipped 0.4%.

Oil prices edged up on Tuesday on hopes that some planned output cuts agreed by OPEC and other producers would be implemented, recovering some ground from losses the previous day over doubts the reductions would rebalance an oversupplied market.

2. GBP slump continues

The British pound dropped to around $1.21 as traders worry about prospects for post-Brexit Britain.

The falling pound - down about 19% versus the dollar since the Brexit referendum - has helped boost the FTSE 100 index in London. It hit an all-time high in early Tuesday trading.

Risky assets are slipping today, Stocks along with the British Pound are tumbling over political uncertainty over Britain's future ties with the European Union and the policies of the incoming U.S. president, Donald Trump.

3. Stocks to watch

Shares in Yahoo could be on the move Tuesday after the company announced that CEO Marissa Mayer will step down from Yahoo's board of directors if its sale to Verizon goes through. The company said it’s going to rename itself to Altaba.

Shares in British grocery chain Tesco are surging in London after the company announced plans to cut about 1,000 jobs and close two distribution centers. It plans to increase hiring at other distribution centers.

In other news, Alibaba Executive Chairman Jack Ma met U.S. President-elect Donald Trump on Monday and laid out the Chinese e-commerce giant's new plan to bring one million small U.S. businesses onto its platform to sell to Chinese consumers over the next five years, an Alibaba spokesman said.

4. Auto sector shines

Top global automakers are going to be in the headlines throughout the day as they make announcements at the Detroit auto show.

General Motors CEO Mary Barra will be presenting details on her expectations for the company and sector.

The industry has been put on the defensive by president-elect Donald Trump, who has threatened GM, Ford (F) and Toyota (TM) with tariffs on cars imported from Mexico.