Taking Documents and Breach of Trust: The Supreme Court Draws a Line

Foreign companies in Korea often assume that any employee who copies internal documents before leaving has committed a crime. That assumption is too broad. On April 24, 2025, the Supreme Court of Korea reversed a conviction in a case that clarifies exactly when removing company data crosses into occupational breach of trust, and when it does not.

This matters for any employer managing departing employees, especially in R&D, manufacturing, or other technical fields where staff routinely handle internal reports and test data.

The Basic Rule: Occupational Breach of Trust

Under Article 355 of the Criminal Act, breach of trust occurs when a person handling another's affairs acts against that duty and gains a benefit, causing loss to the person whose affairs they manage. Article 356 raises the penalty when the offender commits this act "in the course of business," which is why employee data cases are typically charged as occupational breach of trust rather than simple breach of trust.

For years, Korean courts have applied this crime not only to trade secrets under the Unfair Competition Prevention and Trade Secret Protection Act, but also to a broader category called a company's "major business asset." This broader category does not require the strict elements of a trade secret. It only requires that the information have real economic value to the business.

The 2025 Case: Filler Ingredients and a Departing Team Leader

The defendant worked as a production team member, later becoming team leader, at a medical device company that develops dermal filler products. Before resigning in January 2019 to start a competing business, he removed several internal documents: a test report on a specific filler ingredient, an animal implantation study report, and an order sheet related to that ingredient. He later used the same ingredient in products made by his own company and filed a related patent application.

Both the trial court and the appellate court convicted him of occupational breach of trust and imposed a one-year suspended prison sentence. Both courts treated the removed documents as a major business asset because they could reveal the raw material behind the company's filler product.

Why the Supreme Court Reversed

The Supreme Court reversed and remanded - sending the case back to the appellate level - finding that the removed documents did not qualify as a major business asset.

First, the information in the documents was not genuinely confidential. The ingredient's test data was available through the ingredient manufacturer's own public materials, and the animal study results had already been published in an academic thesis. Information that is available to the public through channels outside the company cannot be treated as belonging exclusively to that company.

Second, the order sheet had expired and offered no proof that the company was actually using the ingredient in its current products. A stale commercial document does not show current business practice.

Third, none of the documents described the company's actual manufacturing process or specific technical know-how. They pointed toward an ingredient, not toward how the company made its product.

The Court's underlying standard is worth remembering. Information qualifies as a major business asset only if it is not known to the public, is available in practice only through the party who holds it, took meaningful time, effort, or investment to develop, and would genuinely give a competitor an advantage if used. Simply being useful or related to the business is not enough.

What This Means for Employers in Korea

Companies operating in Korea should not assume that every internal document an employee copies will support a criminal case after the fact. The court will ask whether the specific information was genuinely confidential, current, and tied to real proprietary know-how, not just whether it looked sensitive on its face.

Employers can strengthen their position well before any dispute arises. Mark documents that reflect real proprietary processes as confidential, restrict access on a need-to-know basis, keep licensing and technical files current so outdated documents are not mistaken for evidence of ongoing use.

This post is for general information only and does not constitute legal advice. For guidance on a specific trade secret or employee departure issue, please consult qualified Korean counsel.

© 2026 SJ Chun. All rights reserved. This article may not be reproduced, copied, or republished, in whole or in part, without prior written permission from the author.