In what was widely billed as a diplomatic breakthrough after the August 25 summit between President Lee Jae Myung of South Korea and President Donald Trump, the handshake moment has given way to hard realities as key negotiations remain unresolved. Despite outward displays of unity, the two countries are grappling with deep divisions over tariffs, a massive $350billion investment fund, and defense burden-sharing, underscoring how intertwined economic and security concerns are complicating progress .

South Korean officials quietly acknowledge that, behind the summit's success, substantive agreements-such as a formal joint statement or fact sheet-have failed to materialize. More than a month after preliminary tariffs were agreed, the deal is not yet finalized on paper .

Seoul's National Security Adviser, Wi Sung-lac, explained that while certain areas show notable progress, others lag behind, making it difficult to consolidate documents covering security, trade, economy, and investments . Adding that "one minister's failure can stall another's success," Chief of Staff Kang Hoon-sik highlighted how issues ranging from investments to defense are deeply linked .

At the heart of the friction lies a vast $350billion investment fund. U.S. negotiators pushed for clear structure and direct equity commitments-stances Seoul resisted. The disagreement peaked in a highly charged conference call with U.S. Commerce Secretary Howard Lutnick, described by a senior South Korean adviser, Kim Yong-beom, as "acrimonious" and marked by raised voices. South Korea insists on equity participation only for a fraction of the fund, rejecting broad loan guarantees or direct ownership .

Trade tensions remain unresolved too. The U.S. is pressing for deeper access to South Korea's agriculture market, while Seoul aims to cap tariffs on autos and chips at 15%, aligning with European standards. However, no formal tariff agreement has yet been signed . Domestic manufacturers in Korea are feeling the strain-some reporting "big losses" and ongoing uncertainty.

Defense is another sticking point. Questions remain over how much Seoul will contribute to stationing U.S. forces on its territory, and surprisingly, Trump also raised the issue of the U.S. potentially owning land for its bases-an idea that South Korean officials have deemed politically untenable, with no formal request made .

President Trump, while acknowledging "a problem with South Korea," later claimed that Seoul had "ultimately kept the same deal," though neither side has provided further clarification .

The net result? A summit that delivered optics-but not outcomes. With negotiations over tariffs, agricultural access, investment structure, and defense costs awaiting resolution, South Korea-U.S. ties face challenging roadblocks, and industry stakeholders are watching closely as talks continue.