South Korea announced Tuesday a support package of 33 trillion won ($23.25 billion) for its vital semiconductor industry, as heightened uncertainty over U.S. tariffs threatens domestic companies.

This comes after U.S. president Donald Trump reportedly said he would be announcing the tariff rate on imported semiconductors soon, after exempting them from his steep “reciprocal” tariffs last Friday.

In a social media post Monday, Trump vowed to investigate the “whole electronics supply chain” on national security grounds.

The U.S. Department of Commerce also released a notice saying it will initiate an investigation “to determine the effects on national security of imports of semiconductors, semiconductor manufacturing equipment, and their derivative products.”

South Korea’s funding support was about a quarter more than the 26 trillion committed last year, according to a press release from the finance ministry.

As part of the measures, the government will subsidize the construction of underground power transmission lines to semiconductor clusters, as well as increase the funding ratio for infrastructure in advanced industrial complexes to 50% from 30%.

A total of 20 trillion won of low-interest loans to semiconductor companies will be offered between 2025 and 2027, up from the current 17 trillion won.

Other measures include introducing training and research programs for domestic master’s and doctoral students as well as global joint research programs for foreign talent.

South Korea is home to some of the world’s top chipmakers, including Samsung Electronics and SK Hynix, with semiconductors a key export of the country.

On Tuesday, the South Korean Kospi was up 0.68%, with Samsung climbing 1.07% and SK Hynix up 0.17%.

In 2024, South Korea’s exports of semiconductors stood at $141.9 billion, just over 20% of the country’s $683.6 billion exports.

The U.S. is the second largest export destination for South Korea, with exports rising 10.5% year-on-year to $127.8 billion in 2024, reaching a new annual high for the seventh consecutive year.

On Monday, acting South Korean president Han Duck-soo reportedly said that Trump had “apparently” instructed his administration to conduct immediate tariff negotiations with South Korea, according to local media outlet Yonhap.

Shares of Webull soared nearly 375% on Monday, the second day on the market for the stock-trading app, which completed its merger last week with SK Growth Opportunities Corp., a special-purpose acquisition company (SPAC).

The rally gives Webull a market cap of almost $30 billion.

Webull competes with Robinhood, Charles Schwab and E-Trade. The app lets investors buy and sell shares and options in individual securities, exchange-traded funds and cryptocurrencies, and offers charts, watchlists, screening tools and paper trading.

The company says it has over 23 million registered users and operates in 15 regions globally. In addition to charging fees on trades, Webull has a premium tier with real-time data that costs $40 per year.

In an investor presentation last month, the company said it was expecting $390.2 million in 2024 revenue, which would be roughly flat from 2023.

Former Alibaba and Xiaomi manager Wang Anquan founded Webull in 2016, and he remains the company’s global CEO. Investors include Coatue, General Atlantic and Lightspeed. The app gained popularity during the Covid pandemic, as U.S. citizens used stimulus checks to invest, Anthony Denier, the company’s group president and U.S. CEO, told CNBC in 2021. Webull users are “much more intellectual” than Robinhood’s, Denier has said.

In November, the U.S. House Select Committee on the Chinese Communist Party sent a letter to Denier inquiring about the company’s ties to China. The company didn’t immediately respond to a request for comment.

The rise of blank-check companies such as SK Growth Opportunities peaked in 2021, with 613 IPOs completed, according to SPAC Insider. The market fell apart the following year as soaring inflation and rising interest rates pushed investors out of risky assets. So far this year there have been 23 SPAC IPOs.

Webull said last year that it was planning for its market debut to take place in the second half of 2024.

WATCH: House Committee slams Webull over alleged ties to Chinese Communist Party

Apple shares rose more than 2% on Monday, pushing the company’s market cap back above $3 trillion, as Wall Street expressed some level of relief that the iPhone maker will be able to withstand President Donald Trump’s widespread tariffs.

Late Friday, the Trump administration announced that phones, computers and chips were exempted from new tariffs. Apple is among the most exposed companies to Trump’s tariffs because the majority of its iPhones, iPads and MacBooks are manufactured in China and other Asian countries. Trump has called for Apple to make its products in the U.S.

Most of Apple’s critical imports were exempted from the tariffs, a move that Wall Street analysts said could save Apple billions in costs. However, administration officials warned over the weekend that the exemptions were temporary and could change over the coming weeks.

“I speak to Tim Cook. I helped Tim Cook, recently, and that whole business,” Trump said Monday in a briefing with reporters in the Oval Office, referring to Apple’s CEO. “I don’t want to hurt anybody, but the end result is we’re going to get to the position of greatness for our country.”

Uncertainty about what the future holds helps explain Apple’s relatively muted gain on Friday. The stock is still down almost 9% in April after falling more than 8% in March. The 11% drop in the first quarter marked Apple’s worst performance since 2023.

Apple is the most valuable publicly traded U.S. company once again, edging out Microsoft.

Apple fell below the $3 trillion mark on April 4, two days after Trump announced “reciprocal tariffs” that would place significant duties on China and countries where the company does manufacturing.

The stock rallied last week after Trump announced his administration was dropping new tariff rates to 10% on imports from countries other than China, which would face tariffs as high as 145%.

Analysts at Morgan Stanley wrote in a note Monday that the latest news from the White House brings Apple’s “annualized tariff cost burden” to $7 billion, down from $44 billion as of Thursday.

WATCH: Having exposure to Apple is important