A trading board shows real-time information on the won-dollar exchange rate, the benchmark KOSPI and secondary Kosdaq bourse at a dealing room of Hana Bank in Seoul, Friday. Yonhap

The Korean won could weaken to 1,500 won against the U.S. dollar this week, unsettled by U.S. President Donald Trump's planned car tariffs of 25 percent and the anticipated ruling on the impeachment of President Yoon Suk Yeol, market watchers said Sunday.

Many say the currency of the export-reliant Korean economy is extremely vulnerable to Trump's tariff policies, as evidenced by the currency plunge of over 6 percent in the past four months since the U.S. leader's inauguration.

This is far sharper compared to other major currencies, including the euro, the Japanese yen and the Chinese yuan. Their depreciations were limited to a range of between 0.84 percent and 2.25 percent.

The won-dollar exchange rate is highly likely to register a year-to-date high of over 1,500 won in the April to June period, sparked by months of political turmoil taking an extended political turn if the Constitutional Court fails to impeach Yoon, they say.

According to financial market data, the Korean won traded 1,466.5 against the dollar as of 3:30 p.m., Friday.

This was the sixth consecutive day that the won remained weaker than 1,460 as measured by end-of-day trading figures at 3:30 p.m.

Shinhan Bank researcher Baek Seok-hyun said the won's sensitivity to tariff policies is explained by Korea's high dependence on trade.

This is compounded by Korea losing its competitive edge to China in export products.

"The market share previously dominated by Korea is giving way to China," he said in a report.

A KB Kookmin Bank report also said political uncertainty is putting downward pressure on the Korean currency.

"The Constitutional Court held its last hearing on Feb. 25, but has since delayed the ruling," the report said.

A Hana Bank report said the Korean currency could plunge to weaker than 1,500 won against the dollar.

"Tariff developments are expected to weaken the Korean currency," it said.

"However, it can stop short of that level, if new negotiations or other favorable developments take place."

Korea should brace for a scenario where the 1,500 won level continues for months, leading to a potential downgrade in the country's sovereign credit rating, the report said.

However, the currency will stabilize to around 1,450 won against the dollar, if Yoon is impeached, it added.

Baek said the currency will stabilize further to around 1,400 won by the end of the year, aided by a slowing U.S. economy and the resulting weak dollar.

This, together with economic recoveries in the eurozone and China, will further rein in the U.S. currency.

Similarly, Woori Bank researcher Park Hyung-jung said the figure would remain at around 1,400 won, if the political uncertainty is resolved through Yoon's impeachment.

However, the currency will depreciate to 1,500 won, or weaker, if the impeachment motion is dismissed.

Kim Jin-wook, chief economist at Citi Research Korea, said the impeachment ruling being delayed until after mid-April would lead to greater market volatility and a downgrade in Korea's sovereign credit outlook.