Here are the most important news, trends and analysis that investors need to start their trading day:

• Nasdaq futures slump as control of Senate hangs in the balance
• Democrat Warnock projected to win in Georgia
• Congress set to begin certification of Biden election win
• Covid variant found in South Africa worries experts
• Some taxpayers find relief payments sent to wrong account

1. Nasdaq futures slump as control of Senate hangs in the balance

Dow futures rose but Nasdaq futures fell Wednesday, with control of the Senate looking like it's down to one of Tuesday's two runoff elections in Georgia. Democrats were projected to win one of the races. The other one was too close to call. Democrats need to win both to take the Senate majority away from Republicans. Investors are also watching the latest ADP report on jobs trends at U.S. companies, which showed a decrease of 123,000 positions in December. Estimates had called for a gain of 60,000. On Tuesday, the Dow Jones Industrial Average, S&P 500 and Nasdaq recovered some of the sharp losses from a day earlier.

For the first time since the Covid-triggered market rout in March, the yield on the 10-year Treasury topped 1% on Wednesday. Bond yields move inversely to bond prices. Bitcoin prices rallied above $35,000 early Wednesday, according to data from Coin Metrics. The largest cryptocurrency's latest all-time high comes after a sharp slump Monday and builds on a more than 300% surge in 2020.

2. Democrat Warnock projected to win in Georgia

Democrat Raphael Warnock won one of Tuesday's Senate runoff races in Georgia, according to NBC News projections, beating Republican Sen. Kelly Loeffler to become the state's first Black senator. In Georgia's other runoff election, with nearly all the votes counted, Democrat Jon Ossoff was leading Republican David Perdue, whose Senate term expired Sunday. If Democrats win both races and win the majority in the Senate, the party would control the Senate, the House and the presidency.

3. Congress set to begin certification of Biden election win

The final step in confirming Joe Biden as the next president is set for Wednesday afternoon as Congress convenes to certify that he defeated President Donald Trump in the Electoral College vote. With Biden's 306 electoral votes — 36 more than needed — the process would normally be a formality, but Trump Republicans plan objections.

The outgoing president, who refuses to concede and falsely claims he won the election, is set to address a pro-Trump protest outside the White House on Wednesday morning. Thousands of Trump supporters are expected to attend. At demonstrations Tuesday evening in Washington, police in D.C. said they made six arrests.

4. Covid variant found in South Africa worries experts

A new strain of the coronavirus that emerged in South Africa, like the one discovered recently in the U.K., is proving to be far more transmissible. While able to spread more easily, scientists do not believe either variant is deadlier. But being more transmissible means more people can get infected, which could mean more serious infections and more fatalities. Hoping to stop the spread of the variant found in the U.K., Prime Minister Boris Johnson announced Monday a new national lockdown order for England until at least mid-February. On Monday, New York Gov. Andrew Cuomo announced the first case of the strain in the U.K. was found in upstate.

5. Some taxpayers find relief payments sent to wrong account

Some taxpayers who use tax preparation services said their second Covid relief payments were sent to the incorrect bank accounts, forcing them to wait longer for their money. The IRS and the Treasury Department began issuing the Economic Impact Payments last week. The payment is $600 for each eligible adult and each dependent earning up to $75,000 or $150,000 for married couples filing jointly. Those earning more than that — up to $87,000 for individuals or $174,000 for married couples — are eligible for a reduced payment.

— The Associated Press and NBC News contributed to this report. Follow all the developments on Wall Street in real time with CNBC Pro's live markets blog. Get the latest on the pandemic with our coronavirus blog.