10 things you need to know before the opening bell

Here is what you need to know.

Bitcoin plunges on fears South Korea will shut exchanges. The cryptocurrency trades down more than 10% near $13,800 a coin after the South Korean government warned it may close some cryptocurrency exchanges amid "irrationally overheated" trading.

Bitcoin is losing its dominance over crypto. The digital coin commanded nearly 90% of the crypto market at the beginning of 2017, but that number hit a low of 42% on Monday, according to data from CoinMarketCap.com.

The yield curve is the flattest it's been since 2007. The spread between the 2-year and 10-year yields fell below 51 basis points on Wednesday, making for the tightest it's been since the fourth quarter of 2007.

Oil prices are expected to spend 2018 close to where they are now. West Texas Intermediate crude oil is expected to average $55.78 a barrel next year as OPEC and Russia continue their efforts to curb production and US shale continues to boom, according to a Reuters survey of 32 economists. WTI is currently trading at $59.74.

Tim Cook scored a big raise in 2017. Apple's CEO raked in $12.8 million in 2017, a 46% raise from last year.

A lawyer who once advised Martin Shkreli has been convicted of helping him defraud a pharamceutical company. Evan Greebel, who was outside counsel to Shkreli's former company Retrophin, was found guilty by a federal jury in Brooklyn of charges he conspired to commit wire fraud and securities fraud, Reuters reports.

The world's 500 wealthiest people made $1 trillion in 2017. The 500 wealthiest people in the world got $1 trillion richer in 2017 with their total fortunes hitting more than $5 trillion, according to Bloomberg's Billionaires Index.

Consumer confidence slides off 17-year highs. US consumer confidence slid off 17-year highs in December, falling to 122.1 from 1228.6, according to The Conference Board's monthly survey.

Stock markets around the world are mostly lower. China's Shanghai Composite (-0.92%) trailed in Asia and Germany's DAX (-0.17%) lags in Europe. The S&P 500 is set to open little changed near 2,685.

US economic data is light. Inital claims will be released at 8:30 a.m. ET and Chicago PMI will cross the wires at 9:45 a.m. ET.