Korean news has been saying “Super 301” again for weeks. My coworkers say it. My relatives say it at dinner. It is said the way you say the name of a storm that is coming.
So I went and read what it actually is.
The first thing I found is that Super 301 is not what is happening. Super 301 has not been law since 1990. What is happening is something related, larger, and considerably more consequential — and it landed on my country’s export list this summer, while the tariff proposal that matters most is expected this month.
Here is what I worked out, in the order I worked it out.
The name is wrong
“Super 301” was Section 310 of the Trade Act of 1974, added by the Omnibus Trade and Competitiveness Act of 1988.
Congress created it out of frustration. Regular Section 301 let the President act against unfair trade practices, but it was discretionary, and Congress felt the executive branch used it too sparingly and too piecemeal. So Super 301 made it mandatory: for 1989 and 1990, USTR was required to publish a list of priority foreign countries and priority trade practices, and to open investigations into them.
Then it expired. The original Super 301 provision lapsed in 1990. It was briefly revived by executive order in the 1990s. It is not the legal basis for anything today.
Two things get called “Super 301” that are not:
- Special 301 — an annual report on intellectual property protection. The 2026 edition named Vietnam a Priority Foreign Country, with China, India, Indonesia, Russia, Chile and Venezuela on the Priority Watch List.
- Section 301 — the parent statute. This is the real one. This is what is happening.
I am not being pedantic for the sake of it. The distinction matters because the three tools have different triggers, different targets, and very different sizes. Getting the name wrong makes it impossible to tell how worried to be.
Why Section 301 suddenly matters again
This is the part that reframed the whole thing for me.
On February 20, 2026, the Supreme Court struck down the tariffs. Not some of them — the central pillar. In a 6-3 decision written by Chief Justice Roberts, the Court held that the International Emergency Economic Powers Act does not authorize tariffs at all. IEEPA lets a president “regulate … importation,” and the Court held that regulating importation does not include taxing it. The power to impose tariffs, Roberts wrote, is a branch of the taxing power, and Article I gives that to Congress.
The reciprocal tariffs on most trading partners were invalid. So were the IEEPA tariffs on China, Canada and Mexico. An executive order revoked them within days, and Customs and Border Protection stopped collecting them on February 24.
So the tariff program lost its legal foundation. It did not lose its intent.
What happened next is that the whole thing was rebuilt on a different statute — Section 301. And Section 301 is much harder to challenge, because unlike IEEPA it was written for exactly this purpose. Congress passed it in 1974 specifically to let the executive branch respond to unfair foreign trade practices. It has been used and litigated for fifty years.
That is the honest answer to “why is 301 in the news again.” It is not that the administration discovered a new weapon. It is that the Supreme Court took away the improvised one, and the administration went back to the one that was built for the job.
What has already landed
Temporary worldwide tariffs of 10 percent expired on July 24, 2026. The same day, a new set of Section 301 tariffs took effect on 60 trading partners, ranging from 10 to 12.5 percent, on a forced-labor rationale.
Korea is at 12.5 percent, in the top band alongside Japan and Switzerland.
| Item | Figure |
|---|---|
| Trading partners hit | 60 |
| Tariff range | 10 to 12.5 percent |
| Korea’s rate | 12.5 percent |
| Bilateral agreed ceiling | 15 percent |
| Remaining headroom | 2.5 points |
For scale: Korea exported 122.9 billion dollars to the United States last year and imported 73.4 billion. The US is Korea’s second-largest trading partner.
Korea’s Ministry of Trade, Industry and Resources asked Washington to respect the bilateral agreement reached last year, which caps tariffs on Korean goods at 15 percent. The ministry says the US side reaffirmed that the agreement stands. So 12.5 percent sits under the ceiling — with 2.5 points of headroom.
That headroom is the whole story of what comes next.
The one that has not landed yet
Running separately, and much larger, is a Section 301 investigation into structural excess capacity.
USTR opened it on March 11, 2026 against sixteen economies: China, the European Union, Singapore, Switzerland, Norway, Indonesia, Malaysia, Cambodia, Thailand, Korea, Vietnam, Taiwan, Bangladesh, Mexico, Japan and India.
The theory is worth understanding, because it is not the usual dumping complaint. USTR defines structural excess capacity as industrial capacity sustained by government intervention, which leaves other countries running large or persistent trade surpluses and displaces US production. The accusation is not “you sold below cost once.” It is “your industrial base is bigger than your market because your state made it that way.”
The nine sectors named: steel, aluminum, automobiles, batteries, semiconductors, electronics, chemicals, solar, and ships.
Read that list again. That is not a slice of Korea’s export economy. That is close to a description of it.
The timeline so far: comments closed April 15, hearings ran May 5 to 8, a second comment round closed July 6, and further hearings were held July 7 to 9. Trade lawyers expect a tariff proposal from USTR in August, a comment period after that, and final tariffs in force toward the end of 2026.
That is why the phrase came back into the news this month. Not because anything was decided. Because the proposal is due.
What actually happens if it lands
A tariff is a tax paid by the importer of record — an American company — at the border. It is not a wire transfer from Seoul to Washington. From there it goes one of three ways, usually all three at once:
- The importer absorbs it. Margins shrink. That shows up in US corporate earnings.
- The customer pays it. Prices rise. That shows up in US inflation data, which shows up in Fed decisions.
- The exporter absorbs it. The Korean seller cuts its price to stay competitive. That shows up in Korean corporate earnings and, eventually, Korean wages.
Which of the three dominates depends on who has substitutes. If an American buyer can source the same component from three other countries, the Korean exporter absorbs it. If the Korean supplier is the only one who makes the part to spec, the American buyer absorbs it.
There is also a currency channel that gets ignored. If tariffs shrink Korean exports, they shrink demand for won, and the won weakens against the dollar. For a Korean who holds dollar assets, a weaker won mechanically raises the won value of those assets — which can make a portfolio look healthy in a month when the country’s economy is not.
I wrote a whole post about how stocks, rates and currency actually connect after being confused by exactly that effect in my own account.
So what does this do to my account?
Here is where I had to be honest with myself, and the answer surprised me.
My portfolio is barely exposed. My paycheck is.
What I hold is on this site’s home page: US large-cap index funds, a US dividend fund, a US Treasury position, a small amount of thematic exposure. Almost all of it is American companies. I own the S&P 500, not Korean exporters.
A tariff on Korean steel does not touch an American index fund directly. The second-order effect is real but diluted: some S&P 500 companies import Korean components and their input costs rise, which is one small negative pressure among a thousand.
Meanwhile, I am a mechanical engineer in Korea. The nine sectors named in the investigation are the heavy-manufacturing core of this country’s economy, and trade lawyers list machinery and industrial equipment among the most exposed categories across the whole Section 301 program.
So my human capital — my salary, my job security, the order book of the industry I work in — sits much closer to the path of this policy than my portfolio does. My financial capital sits almost entirely outside it.
I did not plan this. I bought US index funds because I could not pick stocks and I wanted the cheapest broad exposure I could get, which is the same reason I described in why I still buy the S&P 500 when tech stocks crumble. But the effect is that the thing paying my bills and the thing compounding for my retirement are not exposed to the same shock.
If you live in Korea and your salary comes from an exporting industry, your portfolio is the wrong place to also concentrate that bet. Owning a home-country export index on top of a home-country export job is one bet twice, and it is the bet you cannot diversify away from on the job side.
That is not a prediction about tariffs. It is an observation about where my risks already sit.
Where I could be wrong
Nothing has been decided. The excess-capacity proposal has not been published as of this writing. Everything above about its outcome is structure, not forecast.
The 15 percent ceiling may or may not hold. Korea says the US reaffirmed it. Agreements between governments have been reinterpreted before, and 12.5 percent already sits close to the cap.
“My portfolio is not exposed” is too clean. Global supply chains mean tariffs anywhere raise costs somewhere in the S&P 500. And a serious trade war is not good for equities in general, American ones included. I am describing a difference of degree, not immunity.
Currency cuts both ways. A weaker won flatters my dollar holdings in won terms, but it also makes everything I actually buy — food, fuel, imported goods — more expensive. A portfolio that looks better while my grocery bill rises is not obviously a win.
And I am not a trade lawyer. I am an engineer who read the primary documents because the headlines were not specific enough to be useful.
What I am actually doing
Nothing.
The monthly purchase goes in on the same day it always does. I did not move anything in February when the Supreme Court ruling hit, and I am not moving anything in August because a proposal is due.
What I did do is finally learn what the words mean. “Super 301” turned out to be the wrong name for a real thing, and the real thing turned out to matter more to my job than to my account. That is worth knowing, and I did not know it two weeks ago.
I am an engineer writing about my own money, not a financial advisor or a trade lawyer. Nothing here is investment advice. The trade policy described here is accurate as of publication and is actively changing — check primary sources before relying on any of it.