How have Korean patent damages rules been amended?

Chanjoong Kim, Partner · Published 11 November 2026

Last verified 9 October 2026

At a glance: the amendments

The enforcement dates, dates of promulgation and Act numbers in the table were read from the header of each version. [2] The Addenda were read as they appear in the current Patent Act. [1]

The versions of the Patent Act by enforcement date were compared in order, starting from the version of 1 September 1990. The versions in which the text of Article 126-2, 128, 128-2, 130, 131 or 132 changed are the seven in the table. Versions that differ only in spacing and line breaks were not counted. Of the seven, five changed the content of Article 128. The version of 1 January 2015 only revised the wording of Article 128, and the version of 27 May 2025 amended only Article 126-2. Article 128 in the version of 1 July 2001 and in the version of 15 March 2012 has the same text in every paragraph. [2]

The paragraph numbers of Article 128 have moved three times

The same content sits in a different paragraph in each version. “Article 128(1)” in an older decision or publication may be a different provision from the current paragraph (1). [1][2]

The amendments one by one

Starting point: the three paragraphs of the wholly amended Act in force from 1 September 1990

Article 128 of Act No. 4207 had the title “Presumption, etc. of the Amount of Loss” (손해액의 추정등) and 3 paragraphs. [2] Paragraph (1) presumed the amount of profits that the infringer gained from the infringement to be the amount of loss sustained by the right holder. [2] Paragraph (2) allowed the right holder to claim, as the amount of loss, “an amount equivalent to the amount that the patentee or exclusive licensee would ordinarily receive” (통상 받을 수 있는 금액에 상당하는 액) for the working (practice) of the patented invention. [2]

Paragraph (3) provided that, if the loss exceeded the amount in paragraph (2), the excess could also be claimed. The latter part of the same paragraph provided that, if the infringer had no intent or gross negligence, the court could take this into account in setting the amount of damages. [2] The presumption of negligence (Article 130), measures to reinstate business reputation (Article 131) and the submission of documents (Article 132) were also in the same Act. [2]

1 July 2001: the quantity-assigned method and reasonable damages awarded by the court

Act No. 6411 newly inserted paragraphs (1) and (5) in Article 128. [2] The new paragraph (1) allowed the amount of loss to be the quantity of the products assigned by the infringer multiplied by the right holder’s profit per unit. The profit per unit is that of the products that the right holder could have sold if there had been no infringement. [2]

This amount had a cap. The cap was the quantity that the right holder could have manufactured, minus the quantity actually sold, multiplied by the profit per unit. The amount corresponding to the quantity that the right holder could not have sold for a cause other than the infringement also had to be deducted. [2]

The new paragraph (5) dealt with the case where a loss is found to have been incurred but proving the amount of loss is extremely difficult because of the nature of the facts. In that case the court may award reasonable damages based on the entire purport of the pleadings and the results of the examination of evidence. [2] The former paragraphs (1) to (3) were moved to paragraphs (2) to (4). [2]

The statement of reasons for the amendment by the Ministry of Government Legislation (법제처) says that paragraph (1) of Article 128 was newly inserted so that the amount of loss can be calculated easily by confirming only the quantity sold. [3]

1 January 2015: wording revised

Act No. 12753 wholly amended Articles 128, 130, 131 and 132. [2] The statement of reasons for the amendment by the Ministry of Government Legislation says that one strand of this amendment was to revise the sentences of the Act so that they are easier to understand. [3]

The latter part and the proviso of Art. 128(1) were split off into paragraph (2), and the Article came to have 6 paragraphs. [2] In the royalty paragraph, “an amount equivalent to the amount that the patentee or exclusive licensee would ordinarily receive” (통상 받을 수 있는 금액에 상당하는 액) became “the amount that the patentee or exclusive licensee would ordinarily receive” (통상적으로 받을 수 있는 금액). [2] The Korean word for proof was changed from “입증” to “증명”, and the Korean word for taking into account was changed from “참작” to “고려”. [2]

30 June 2016: the claim for compensation for loss stated in the Act, and the order to submit materials

Act No. 14112 newly inserted paragraph (1) in Article 128. It provides that a patentee or exclusive licensee may claim compensation for the loss caused by the infringement from a person who has intentionally or negligently infringed the right. [2] The title of the Article was changed from “Presumption, etc. of the Amount of Loss” (손해액의 추정 등) to “Claim for Compensation for Loss, etc.” (손해배상청구권 등). [2] The former paragraphs (1) to (6) were moved to paragraphs (2) to (7). [2]

All six of the moved paragraphs were amended by this Act. In paragraphs (2), (4) and (5), the opening words were shortened to “where compensation for a loss is claimed pursuant to paragraph (1)”. In paragraphs (3), (6) and (7), the paragraph numbers cited were changed. [2]

The same Act newly inserted Article 128-2. Where the court orders an expert appraisal to calculate the amount of loss, a party must explain the matters necessary for the appraisal to the appraiser. [1][2]

The title of Article 132 was changed from “Submission of Documents” (서류의 제출) to “Submission of Materials” (자료의 제출), and the Article came to have 5 paragraphs. [2] Before the amendment, the provision covered documents necessary for calculating the loss. After the amendment, it covers materials necessary for proving the infringement or calculating the amount of loss. [2]

• Paragraph (2): where the person possessing the materials argues that there is a reasonable ground to refuse to submit them, the court may order the materials to be presented in order to decide whether the argument is right. The court must not allow other persons to see the materials. [1]
• Paragraph (3): even where the materials are a trade secret, this is not regarded as a reasonable ground if the materials are indispensable for proving the infringement or calculating the amount of loss. In that case the court must designate the scope in which, or the persons by whom, the materials may be inspected. [1]
• Paragraph (4): where a party does not follow the order without a reasonable ground, the court may find the other party’s assertion on what the materials state to be true. [1]
• Paragraph (5): where paragraph (4) applies and two requirements are met, the court may also find the assertion on the fact to be proved to be true. The party who made the request must be in a situation where it is extremely difficult to assert in detail what the materials state. It must also be difficult to expect that fact to be proved by other evidence. [1]

“Materials submitted or to be submitted pursuant to Article 132(3)” was added to Art. 224-3(1), subparagraph 1. These materials came to be covered by a request for an order to maintain confidentiality. [2] The definition of a trade secret that had been in Art. 224-3(1) was moved to Art. 132(3). [1][2]

Article 8 of the Addenda provides that the amended provisions of Articles 128-2, 132 and 224-3 apply “from the first action filed after this Act enters into force”. [1] The Addenda to Act No. 14112 contain no applicability provision on the amendment of Article 128. [1] The submission of materials and the means of proof are covered in “How is patent infringement proven in Korea without US-style discovery?”.

9 July 2019: reasonable royalty, award of up to 3 times, and specific type of behavior

Act No. 16208 changed three things. [2][3]

First, “the amount that the patentee or exclusive licensee would ordinarily receive” (통상적으로 받을 수 있는 금액) in Art. 128(5) became “the amount that the patentee or exclusive licensee would reasonably receive” (합리적으로 받을 수 있는 금액). [2] Art. 65(2) and Art. 207(4), which provide for compensation after the laying-open of the application, were changed to the same word. [2] The Addenda to Act No. 16208 contain no applicability provision for these three provisions. [1]

Second, paragraphs (8) and (9) were newly inserted in Article 128. Paragraph (8) allowed the court, where the infringement is found to be intentional, to set the award at up to 3 times the amount recognized as loss. [2] The amount recognized as loss is the amount recognized under paragraphs (2) to (7). [2] Paragraph (9) sets out eight factors that must be considered in determining that award. [1]

1. Whether the infringer is in a superior position
2. The degree of intent, or of awareness of the risk that loss would occur
3. The scale of the harm that the patentee and the exclusive licensee suffered from the infringement
4. The economic benefit that the infringer gained from the infringement
5. The duration, frequency, etc. of the infringement
6. The fine for the infringement
7. The financial condition of the infringer
8. The degree of the infringer’s effort to remedy the harm

The statement of reasons for the amendment by the Ministry of Government Legislation calls this system a “punitive damages system” (징벌적 손해배상제도). The Article does not use that term. [1][3] The statement of reasons says that factors such as whether the infringer is in a superior position are considered in deciding whether the infringement is intentional. The Article provides that they are considered “in determining the award under paragraph (8)”. This article follows the Article. [1][3]

Article 3 of the Addenda provides that paragraphs (8) and (9) apply “from the first case in which a violation occurs after this Act enters into force”. [1]

Third, Article 126-2 was newly inserted with 4 paragraphs. [2]

• Paragraph (1): a party who denies the specific type of behavior of the infringement asserted by the right holder must present its own specific type of behavior. [2]
• Paragraph (2): where the party argues that there is a good reason for being unable to present it, the court may order that party to submit materials in order to decide whether the argument is right. This does not apply where the person possessing the materials has a good reason to refuse to submit them. [2]
• Paragraph (3): Art. 132(2) and (3) apply mutatis mutandis to the order to submit materials under paragraph (2). [2]
• Paragraph (4): where the party does not present it without a good reason, the court may find the type of behavior asserted by the right holder to be true. [2]

Article 2 of the Addenda provides that this Article applies “from the first litigation on infringement of a patent or exclusive license filed after this Act enters into force”. [1]

10 December 2020: a royalty also for the quantity above the spare production capacity

Act No. 17422 amended Art. 128(2) and deleted paragraph (3). [2] The former paragraph (3) capped the amount at the right holder’s spare production capacity multiplied by the profit per unit. The quantity above the spare production capacity was not included in the amount of loss under this method. [2]

The amended paragraph (2) allows the sum of two amounts to be the amount of loss. [1]

• Subparagraph 1: the part of the quantity of the products assigned that does not exceed the right holder’s spare production capacity, multiplied by the profit per unit. The quantity that the right holder could not have sold for a cause other than the infringement is first subtracted from the quantity of the products assigned. [1]
• Subparagraph 2: the amount that the patentee or exclusive licensee would reasonably receive for the quantity above the spare production capacity and for the quantity that could not have been sold for a cause other than the infringement. [1]

Here, “spare production capacity” is a short name for the quantity of products that the right holder could have manufactured minus the quantity of products actually sold. [1] Subparagraph 2 has an exclusion. Where the right holder is not found to have been able to grant an exclusive license or a non-exclusive license, that quantity is subtracted. [1]

Article 2 of the Addenda provides that the amended Article 128 applies “from the first case in which damages are claimed after this Act enters into force”. [1] The reference point of this Addenda provision is the time when damages are claimed. It contains no wording that divides the application by the time when the infringement took place. [1]

Example: the difference between the former and the amended provision

The figures below are assumed. The quantity of the products assigned by the infringer is 10,000 units, and the right holder’s spare production capacity is 6,000 units. There is no quantity that could not have been sold for a cause other than the infringement. The profit per unit is KRW 1,000, and the amount that the patentee or exclusive licensee would reasonably receive is KRW 100 per unit. The right holder is found to have been able to grant a non-exclusive license for the remaining 4,000 units.

The quantity under subparagraph 2 of the amended paragraph (2) is the 4,000 units that exceed the spare production capacity of 6,000 units, out of the 10,000 units assigned. [1]

The calculation methods of Article 128 are covered in detail in “How are damages calculated in Korean patent cases?”.

21 August 2024: the cap goes from 3 times to 5 times

Act No. 20322 changed “3 times” in Art. 128(8) to “5 times”. These are the only words that changed. [2] The eight factors in paragraph (9) were not amended. [1][2] Article 2 of the Addenda provides that the amended paragraph (8) applies “from violations that occur on or after the date this Act enters into force”. [1]

The requirements for enhanced damages and their application by the courts are covered in “When are enhanced damages available in Korea?”.

27 May 2025: the terms in Article 126-2

Act No. 20975 changed “type of behavior” (행위태양) in Article 126-2 to “details, manner and form of the act” (행위의 내용ㆍ방식ㆍ형태). The title and paragraphs (1) to (4) were amended. [1][2] The statement of reasons for the amendment by the Ministry of Government Legislation says that the terms were revised so that the public can understand the Act easily. [3] This Act entered into force on the date of its promulgation, and its Addenda contain no applicability provision. [1]

Articles unchanged since 1990

Article 130 presumes that a person who has infringed another person’s patent or exclusive license was negligent regarding that infringement. The main text is the same in the version of 1 September 1990 and in the current version. [1][2]

Article 131 provides for the measures necessary to reinstate business reputation. Its sentences were tidied when the Article was wholly amended with effect from 1 January 2015. The framework, under which the measures may be ordered in lieu of damages or together with damages, was already in the version of 1 September 1990. [1][2]

The same Articles apply mutatis mutandis to utility model rights

Article 30 of the Utility Model Act (실용신안법) applies Articles of the Patent Act mutatis mutandis to the protection of holders of utility model rights. The Articles so applied are Articles 126, 128, 128-2 and 130 to 132 of the Patent Act. [5] Article 126-2 of the Patent Act is not among the Articles listed in Article 30. [5]

Article 128-2 was added to Article 30 of the Utility Model Act by Article 10 of the Addenda to Act No. 14112 amending the Patent Act. [1] Article 30 of the amended Utility Model Act that enters into force on 16 March 2027 (Act No. 21953) has the same text as the current Article. [5]

Cases that straddle the enforcement date

The reference point used by the Addenda differs for each amendment. Several reference points can apply to one case at the same time. [1]

Cases that the wording of the Addenda reaches

The enhancement provisions are divided by the time when the violation occurs. Article 3 of the Addenda to Act No. 16208 covers the first case in which a violation occurs after the Act entered into force on 9 July 2019. Article 2 of the Addenda to Act No. 20322 covers violations that occur on or after the date the Act entered into force, 21 August 2024. [1][2]

Neither of the two Addenda has wording that separately addresses infringement that began before the enforcement date and continued after it. [1] Article 3 of the Addenda to Act No. 16208 has the word “first” (최초로), and Article 2 of the Addenda to Act No. 20322 does not. [1] How the courts have read this wording is covered in “When are enhanced damages available in Korea?”.

The amendment of Art. 128(2) is divided by the time when damages are claimed. Article 2 of the Addenda to Act No. 17422 has no wording that divides the application by the time when the infringement took place. [1] The two Addenda on the enhancement provisions use the time when the violation occurs as the reference point. [1] Paragraphs (2) and (8) of Article 128 have different reference points under the Addenda.

Cases that the Addenda do not address

The amendments below have neither an applicability provision nor a transitional measure. The Addenda do not provide which version applies to infringement before the enforcement date or to litigation pending on the enforcement date. [1]

• The new Art. 128(1) and the move of the paragraph numbers, in force from 30 June 2016 (Act No. 14112)
• “Reasonably” in Art. 128(5), Art. 65(2) and Art. 207(4), in force from 9 July 2019 (Act No. 16208)
• The revision of terms in Article 126-2, in force from 27 May 2025 (Act No. 20975)

Article 8 of the Addenda to the amendment in force from 1 January 2015 (Act No. 12753), which wholly amended these Articles, is a general transitional measure. It provides that patent applications filed before that Act entered into force, and the examination of and trials on those patent applications, are governed by the former provisions. This wording does not mention litigation. [1]

Paragraph (3) of the Addenda to the amendment in force from 1 July 2001 (Act No. 6411) is also a general transitional measure. It provides that the patent rights and litigation on patent applications filed under the former provisions at the time that Act entered into force are governed by the former provisions. [1] Article 128 is not among the five subparagraphs of its proviso. [1]

Amendments promulgated but not yet in force, and subordinate statutes

As of 9 October 2026, the only Patent Act listed by the Ministry of Government Legislation as scheduled to enter into force is Act No. 21955. It was promulgated on 15 September 2026 and enters into force on 16 March 2027. [4] Compared with the current version, the Articles whose text differs are two: Articles 81-3 and 87. The Articles covered in this article are unchanged. [4]

Articles 128, 128-2, 132 and 126-2 delegate nothing to a Presidential Decree or a Prime Ministerial Decree. [1] This article did not check whether a bill to amend the damages provisions has been introduced.

What right holders should do

• In general, we suggest dividing the period of infringement at 9 July 2019 and at 21 August 2024. The two Addenda on the enhancement provisions use these enforcement dates as the reference point.
• We suggest confirming the date on which damages were claimed. The amendment of Art. 128(2) is divided by the time when damages were claimed, with 10 December 2020 as the reference date.
• We suggest reading the paragraph numbers in older decisions and publications against the text of the version concerned. The same “Article 128(2)” is a different provision in each version.
• If the spare production capacity is smaller than the quantity of the products assigned, we suggest also preparing royalty materials for the excess quantity.
• Please confirm with your agent which version applies to an individual case.

FAQ

Does the 5 times cap apply to infringement before 21 August 2024?

Article 2 of the Addenda to Act No. 20322 provides that the amended Art. 128(8) applies from violations that occur on or after the date that Act entered into force. The enforcement date is 21 August 2024. [1][2] The cap before that was 3 times, and the 3 times provision entered into force on 9 July 2019. [2]

From when can a royalty be claimed for the quantity above the spare production capacity?

The amended Art. 128(2) entered into force on 10 December 2020. [2] Article 2 of the Addenda to Act No. 17422 provides that it applies from the first case in which damages are claimed after that Act entered into force. [1] The reference point is the time when damages are claimed, not the time of the infringement. [1]

What happens if a party does not follow an order to submit materials?

Where a party does not follow the order without a reasonable ground, the court may find the other party’s assertion on what the materials state to be true (Art. 132(4)). [1] Where the requirements of paragraph (5) are met, the court may also find the assertion on the fact to be proved by the materials to be true. [1] Article 8 of the Addenda to Act No. 14112 provides that the amended Article 132 applies from the first action filed after that Act entered into force. The enforcement date is 30 June 2016. [1][2]

Does the amendment in force from 16 March 2027 change the damages provisions?

It does not. The Articles amended by Act No. 21955 are Articles 81-3 and 87. [4]

How DEFINE IP Law Firm handles this

When DEFINE IP Law Firm reviews damages, we first set out the period of infringement and the time of the claim. Based on those two points, we confirm which version of Article 128 of the Patent Act applies. When we cite decisions and publications, we match the paragraph numbers of that version against the current Article. For questions about the damages provisions for Korean patents, please write to contact@defineip.kr.

Sources

1. Ministry of Intellectual Property (지식재산처), Patent Act (특허법), Act No. 21134, in force from 2025-11-11. Articles 65, 126-2, 128, 128-2, 130, 131, 132, 207 and 224-3; Addenda (Act No. 6411, paragraph (3); Act No. 12753, Art. 8; Act No. 14112, Art. 8 and Art. 10; Act No. 16208, Art. 2 and Art. 3; Act No. 17422, Art. 2; Act No. 20322, Art. 2; Act No. 20975). https://www.law.go.kr/법령/특허법 (verified 2026-10-09)
2. Ministry of Intellectual Property (지식재산처), Patent Act (특허법), previous versions. Article 128 and the surrounding Articles of Act No. 4207 (in force from 1990-09-01), Act No. 6411 (in force from 2001-07-01), Act No. 11117 (in force from 2012-03-15), Act No. 12753 (in force from 2015-01-01), Act No. 14112 (in force from 2016-06-30), Act No. 16208 (in force from 2019-07-09), Act No. 17422 (in force from 2020-12-10), Act No. 20200 (in force from 2024-08-07), Act No. 20322 (in force from 2024-08-21) and Act No. 20975 (in force from 2025-05-27); list of versions by enforcement date. https://www.law.go.kr/법령/특허법 (verified 2026-10-09)
3. Ministry of Government Legislation (법제처), statements of reasons for the enactment and amendment of the Patent Act (특허법 제정·개정이유). Act No. 6411, Act No. 12753, Act No. 14112, Act No. 16208, Act No. 17422, Act No. 20322 and Act No. 20975. https://www.law.go.kr/법령/특허법 (verified 2026-10-09)
4. Ministry of Intellectual Property (지식재산처), Patent Act (특허법), Act No. 21955, promulgated 2026-09-15, in force from 2027-03-16. Comparison of all Articles with the current version. https://www.law.go.kr/법령/특허법 (verified 2026-10-09)
5. Ministry of Intellectual Property (지식재산처), Utility Model Act (실용신안법), Act No. 21065, in force from 2025-10-01, Article 30. Utility Model Act (실용신안법), Act No. 21953, promulgated 2026-09-15, in force from 2027-03-16, Article 30. https://www.law.go.kr/법령/실용신안법 (verified 2026-10-09)