10 things you need to know before the opening bell

Matt Dunham/AP

British Prime Minister Theresa May leaves 10 Downing Street heading to Parliament for Prime Minister's questions in London, Wednesday, Nov. 14, 2018.

Here is what you need to know.

The British pound is under pressure. The pound extended declines against the dollar, trading down 1.5%, after a key cabinet member joined Brexit secretary Dominic Raab in resigning in protest of Theresa May's plan to leave the EU.

Bitcoin tumbles to its lowest level in over a year. The world's largest cryptocurrency fell more than 13% Wednesday to as low as $5,3222 a coin. On Thursday, bitcoin cash, the fourth-largest cryptocurrency by market cap, is set to experience a hard fork amid a fight that is playing out between its two biggest proponents, Craig Wright and Roger Ver.

Warren Buffett's Berkshire Hathaway takes a new stake in JPMorgan. The firm bought nearly $4 billion worth of the bank's shares and increased its holdings of other financial companies, according to a third-quarter regulatory filing.

Apple slides into a bear market. The world's most valuable company has dropped more than 20% from its October peak amid analyst downgrades and concerns about weaker demand for iPhones.

Uber's losses are widening and its growth is slowing. While revenue is still climbing steadily, the third-quarter increase by 38% was down from its 63% year-over-year jump in the second quarter, according to data released to select media outlets.

Traders haven't been this worried about tech stocks for 14 years, and its a negative signal. The spread between the Cboe Nasdaq Volatility Index (VXN) - which tracks the tech-heavy Nasdaq 100 - and its S&P 500 counterpart (VIX) is the widest since 2004.

Levi's is reportedly planning to go public. The denim apparel maker aims to make its initial public offering in the first quarter of 2019 at a valuation of about $5 billion, according to CNBC.

US economic data is on deck. Initial jobless claims, retail sales, Empire State manufacturing, and the Philly Fed manufacturing survey all cross at 8:30 a.m. ET.

Earnings reporting continues. Ahead of the market open, Walmart reported better-than-expected profits but missed on revenue. Nordstrom, Nvidia, and Sonos report after the closing bell.

Stock futures are higher. Dow futures are up 102 points, or 0.4%, while S&P 500 futures are up 0.3%.