Jan 28 (Reuters) - U.S. President Donald Trump plans to

impose tariffs on imported computer chips, pharmaceuticals and

steel, he said on Monday, to push companies to manufacture more

in the United States.

The comments mark the latest in a number of trade-related

threats unleashed by Trump in recent days. He has already

promised to slap 25% tariffs on imports from Canada and Mexico

by Feb. 1 if the two countries don't meet demands on border

security and other issues.

By focusing on chips and pharmaceuticals, Trump could

squeeze U.S. allies in Asia, including Taiwan, South Korea and

Japan.

WHAT'S BEING TARGETED FOR CHIPS?

Trump said he plans to impose tariffs on imported computer

chips without providing details.

Asia is the world's biggest chip manufacturing hub,

producing more than 80% of semiconductors sold globally,

according to the Asian Development Bank.

Taiwan Semiconductor Manufacturing Co. ( TSM ) , the

world's largest contract chipmaker, makes semiconductors for

Nvidia ( NVDA ), Apple and other U.S. clients. TSMC generated 70% of its

revenue in 2024 from customers based in North America.

While it is building a $65 billion manufacturing facility in

Arizona, the bulk of TSMC's production remains in Taiwan, with

exports to the U.S. theoretically subject to tariffs.

WHAT ABOUT OTHER CHIPS?

Asian producers also dominate the market for memory chips,

with DRAM and NAND flash chips used in electronic devices

including computers.

South Korea's Samsung Electronics ( SSNLF ) and SK Hynix ( HXSCF )

together control around three quarters of the global

DRAM market.

The two companies, plus Japan's Kioxia, which is controlled

by U.S. buyout firm Bain Capital, command a similar market share

in NAND flash.

Samsung is investing roughly $44 billion in chipmaking

facilities in Texas with subsidies from the U.S. government.

WHAT ABOUT THE ECONOMIC HIT?

Chips are a major source of export revenue for South Korea

and Taiwan, meaning there's a lot more at stake than just the

impact on manufacturers themselves.

South Korea's exports of semiconductors hit a record $141.9

billion in 2024, of which $10.28 billion was to the U.S.,

according to data released by the Ministry of Trade, Industry

and Energy earlier this month.

WHAT ABOUT OTHER CHIP SUPPLY CHAIN COMPANIES?

Japan is a major supplier of chipmaking equipment and

materials, all of which, at least for now, appear to have

avoided direct mention by Trump. Major equipment companies

include Tokyo Electron ( TOELF ) and Advantest ( ADTTF ).

WHAT ABOUT PHARMA?

Imposing tariffs on imported pharmaceuticals could weigh on

Japan, home of major drugmakers such as Takeda, Astellas,

Daiichi Sankyo ( DSKYF ) and Eisai ( ESALF ), which has been expecting strong sales

growth in the U.S. of its Alzheimer's disease drug Leqembi.

For Takeda, the U.S. market accounted for just over half of

its revenue in last financial year, while for Astellas it

accounted for 41%. In both cases it wasn't clear how much of the

U.S. revenue came from imports.

In a statement, Astellas said it was always preparing for

geopolitical risks to ensure a stable supply of products. It

also said it had invested in multiple manufacturing sites in the

U.S. and would continue to do so.