The US 100% tariff on pharmaceutical imports took effect today, 29 September 2026. Hours before it did, reports confirmed India is one of 20 jurisdictions exempted from the levy on certain speciality drugs — specifically rare-disease treatments, gene and cell therapies, and fertility drugs. Indian pharma headlines read "big relief."

Read the exemption list again, though. Rare-disease drugs, gene therapies and fertility treatments are not what India sells to America. India sells generics. And the one large Indian pharma company that has spent five years deliberately walking out of generics and into branded, patented, innovator medicines — the exact category the 100% tariff was built for — is Sun Pharma.

Sun Pharma's own annual report describes the trap

Sun's FY26 annual report (filed with NSE on 6 July 2026) reads the policy candidly: "Pharmaceutical tariffs have re-entered policy focus... policy discussions increasingly distinguish between innovator drugs and affordability-critical products. Generics, and in several cases, biosimilars are expected to benefit from exemptions or reduced tariff exposure."

That is Sun correctly predicting the architecture of today's tariff. The same annual report shows Sun moving from the protected side of that line to the exposed side.

Per the FY26 annual report, the US contributed 29% of Sun's consolidated revenues (31% in FY25), and Sun holds the No. 2 position by prescriptions in the US dermatology market. Per the Q4 FY26 results release (22 May 2026), Sun's Innovative Medicines business crossed USD 1 billion in revenues — the division was called "Specialty" until it was renamed in FY26. Per the Q2 FY26 earnings call transcript (11 November 2025), managing director Kirti Ganorkar reported Global Innovative Medicines sales of USD 313 million, up 16.4%, and noted that "U.S. sales of Innovative Medicine has surpassed generics for the first time during the quarter."

By the Q1 FY27 call (6 August 2026), innovative medicine sales were USD 351 million, up 12.8%, accounting for 21.9% of total Sun sales. Sun's largest innovative brand, Ilumya (tildrakizumab), reported USD 580 million of sales in FY24 per its investor presentations, and is now commercialised across 35 markets.

So roughly a fifth of Sun's revenue sits in branded, on-patent medicines, with the US the largest contributor. Yesterday's exemption covers rare-disease, gene/cell and fertility products. Ilumya is a psoriasis biologic. It is not on that list.

The disclosure gap that matters

Whether Sun actually pays the tariff depends on where each product is physically made — precisely what Sun will not tell investors.

On the Q1 FY26 earnings call (transcript filed 6 August 2025), an analyst asked about improving the US manufacturing footprint. Richard Ascroft, who runs Sun's North America business, answered: "We actually have a significant footprint in the United States already. And at this time, we have no plans to move further manufacturing to the U.S." Asked the follow-up — what percentage of sales comes from the US plant — investor relations head Abhishek Sharma replied: "That we don't disclose."

That refusal is the most important unquantified number in Indian pharma right now. Sun has told the market it will not onshore further, and will not say how much it already onshores.

Who the exemption actually helps: Zydus

If you want the company that genuinely benefits from a rare-disease carve-out, the filings point at one name. Zydus Lifesciences has built a US orphan-drug franchise through its wholly owned subsidiary Sentynl Therapeutics.

Per the Q4 FY26 investor presentation (24 May 2026), Zydus launched Zycubo (copper histidinate) for Menkes disease, "an ultra-rare disease," and stated: "With this launch, we now have 3 rare disease products marketed by Sentynl." The Q3 FY26 presentation (15 February 2026) records that Zycubo got final USFDA approval in January 2026 and "has become the first and only therapy approved for the treatment of Menkes disease." The other two: NULIBRY (fosdenopterin) for Molybdenum Cofactor Deficiency Type A, and Zokinvy (lonafarnib) for Hutchinson-Gilford Progeria Syndrome, acquired worldwide from Eiger Biopharmaceuticals in May 2024.

Per the Q1 FY27 presentation (18 August 2026), Zydus said "our branded business in the US now contributes 10% of our revenue in the US," listing growth drivers as "orphan and rare disease franchise, a growing portfolio of 505(b)(2) products, the recent acquisition of Rolvedon, and an NDA submission to the USFDA of Saroglitazar." A companion slide dated 23 August 2026 puts US Specialty at ">10% of North America Sales in Q1FY27."

Zydus is the rare Indian company whose branded US portfolio sits inside the exempted categories rather than outside them.

The quietly insulated

Senores Pharmaceuticals manufactures inside the United States. Its Q1 FY27 presentation (27 July 2026) describes a "USFDA approved facility in Atlanta, US and Gujarat, India," with 58 ANDAs approved across 187 strengths. On its 30 July 2025 call, management said the "DEA and BAA certifications for our manufacturing facility in the US gives us a considerable advantage over competitors." A US plant is tariff-proof by construction. Aurobindo Pharma made the trade-off explicit on its 8 August 2025 call: "we have a fourth facility that we can always do it with some time. So we are best suited for enhancing our footprint in the US." The same executive added the caveat most commentary skips: "Practically, if it's manufactured in US, the product pricing would go up higher... US would be different price levels altogether." Lupin says its branded US book is small. On its 21 May 2025 call, CEO Vinita Gupta said: "We don't see a direct impact on our brand products which are relatively speaking small in the scheme of things."

What retail investors should do

Do not treat today's exemption as sector-wide relief. It is a narrow, category-based carve-out that maps onto almost nothing in India's US export mix except Zydus's three Sentynl products.

Instead, invert the usual framing. For three years, "shifting from generics to specialty" was the bull case for Indian pharma, and Sun executed it better than anyone. Today that same shift is the tariff exposure. Ask each company two questions its filings can answer: what share of US revenue is branded and on-patent, and where is it manufactured? Zydus, Lupin and Senores answer both. Sun answers the first — roughly 22% of group sales are Innovative Medicines — and explicitly declines to answer the second. Watch Sun's Q2 FY27 call, due late October 2026, for whether "no plans to move further manufacturing to the U.S." still holds; a reversal would signal real capex, and real margin pressure, ahead.

Data sourced from company filings on NSE via Xaro.