• Stock futures were lower as investors braced for President Donald Trump's new tariffs.
• Mixed martial arts league UFC has struck a multimillion-dollar, multiple-year partnership deal with Meta.
• Boeing CEO Kelly Ortberg will testify before a U.S. Senate committee as he looks to assure Congress of the plane maker's path to recovery.

Here are five key things investors need to know to start the trading day:

1. Brace for impact

Stock futures were lower Wednesday morning as investors braced for President Donald Trump's new tariffs set to be announced later in the day. The S&P 500 closed higher Tuesday after whipsawing in another volatile session, adding 0.38%, and the Nasdaq Composite gained 0.87%. The Dow Jones Industrial Average, meanwhile, slipped 11.80 points, or 0.03%. But tariff uncertainty wasn't the only thing weighing on markets Tuesday: Weaker-than-expected economic data also pressured stocks. Follow live market updates.

2. 'Liberation day'

President Trump is expected to unveil his sweeping "reciprocal tariffs" plan on Wednesday, on what he's dubbed 'liberation day,' and investors are hoping the announcement will offer clarity on the president's trade policy. But the scope and severity of the new tariffs — which will target countries that have their own import duties on U.S. goods — remain unknown. White House aides have reportedly drafted a proposal that would levy a roughly 20% tariff on most imports. White House Press Secretary Karoline Leavitt on Tuesday said that Trump "said last night he has made a decision" on the level of tariffs he will impose. Leavitt also said the duties will take effect immediately after they're announced. The president is set to deliver remarks at a "Make America Wealthy Again" event in the Rose Garden at 4 p.m. ET, according to the White House. Follow live tariff updates.

3. Off to a hot start

Shares of Newsmax and CoreWeave — both of which debuted on the public markets in recent days — surged higher Tuesday. Shares of conservative cable channel Newsmax closed up nearly 180% in its second day of trading, putting the stock more than 1,500% above its IPO price on Monday. AI company CoreWeave had a more tempered launch after starting trading on Friday, closing flat on its first day and dropping 10% on Monday. But shares popped Tuesday, climbing nearly 42% to bounce back above its IPO price. After a quiet couple of years, there have been signs of life for the IPO market. Circle, the company behind the USDC stablecoin, filed for an IPO on Tuesday — its second attempt at going public. The crypto company plans to list on the New York Stock Exchange.

4. Teaming up

UFC is teaming up with Meta. The mixed martial arts league, owned by TKO Group, has struck a multimillion-dollar, multiple-year partnership deal with the tech giant, CNBC reported Wednesday. As part of the deal, which is separate from the UFC's media rights discussions, Meta will become the "official fan technology partner" of UFC. The league's integration with the tech giant will span Meta's many products — including Meta AI, Meta Glasses, Meta Quest, Facebook, Instagram, WhatsApp and Threads — and brings Meta CEO Mark Zuckerberg closer to UFC CEO Dana White, who joined the Meta board in January.

5. This is your captain speaking

Boeing CEO Kelly Ortberg is set to testify before a U.S. Senate committee on Wednesday as he looks to assure Congress of the plane maker's path to recovery following manufacturing and safety crises. "Boeing has made serious missteps in recent years — and it is unacceptable. In response, we have made sweeping changes to the people, processes, and overall structure of our company," Ortberg said in written testimony seen by CNBC before the hearing. The CEO will face the U.S. Senate Committee on Commerce, Science and Transportation in a hearing set to begin at 10 a.m. ET.

— CNBC's Brian Evans, Lisa Kailai Han, Sean Conlon, Jeff Cox, Kevin Breuninger, Jesse Pound, Sarah Min, Jacob Pramuk, Lillian Rizzo, Samantha Subin, MacKenzie Sigalos, Tanaya Macheel, Alex Sherman and Leslie Josephs contributed to this report.