In light of the judicial decisions examined; while the issue of whether interest can be accrued from the date of the lawsuit on the amount increased by the petition for increasing the claim amount in an unliquidated claim lawsuit differs according to the qualification of the lawsuit (whether it is an unliquidated claim lawsuit or a partial lawsuit) and periodic changes in the jurisprudence of the Supreme Court chambers, it has been determined that the current and prevailing view is in favor of “accruing interest from the date of the lawsuit.”

1. General Rule: In Unliquidated Claim Lawsuits, Interest Starts from the Date of the Lawsuit 

The Supreme Court General Assembly of Civil Chambers, many Supreme Court chambers, and Regional Courts of Justice, in cases where the lawsuit is an unliquidated claim lawsuit duly filed within the scope of Article 107 of the HMK (Code of Civil Procedure), have ruled that interest should be accrued on the entire claim, including the amount increased by the petition for increasing the claim amount, from the date of the lawsuit.

Legal Rationale: In an unliquidated claim lawsuit, in situations where there is no default occurring before the date of the lawsuit, default for the entire claim is deemed to have occurred on the date the lawsuit was filed. The increase in the claim amount is not an amendment but a completion process within the scope of Article 107 of the HMK, and the effect of interrupting the statute of limitations begins on the date of the lawsuit.

Supporting Decisions:

Supreme Court General Assembly of Civil Chambers (2021/931): Stated that default occurred on the date of the lawsuit for the entire claim, the amount of which was fully and definitively determined in the unliquidated claim lawsuit, and therefore, interest should be accrued on the entire claim, including the amounts increased by the petition for increasing the claim, from the date of the lawsuit.

Court of Cassation 3rd Civil Chamber (2017/2320, 2024/2568, 2025/1964): found it erroneous that the interest start date for the increased amount was not specified or was determined as the amendment date; it emphasized that interest should be awarded from the date of the lawsuit for the increased portion as well.

Court of Cassation 7th Civil Chamber (2014/13803, 2014/18603K, 2015/24933, 2016/12588K): deemed it a ground for reversal that the petition for increasing the claim was considered an amendment and interest was started from the date of increase, and stated that interest should accrue on the entire receivable from the date of the lawsuit.

Court of Cassation 17th Civil Chamber (2016/5952): Stating that the increase was not an amendment, it ruled that interest should be awarded from the date of the lawsuit for the increased portion as well.

Regional Courts of Justice (İzmir RCJ 11th CC, İzmir RCJ 20th CC, İstanbul RCJ 12th CC, Adana RCJ 3rd CC): In their appellate reviews, by revoking or amending the local court decisions that applied interest to the increased portion from the amendment/increase date, they determined the interest start date as the lawsuit date (or the default date).

2. Change in View and Different Practices of the Court of Cassation 9th Civil Chamber In the decisions of the Court of Cassation 9th Civil Chamber, a change in jurisprudence or a dual distinction has been observed over time.

Current Approach (Date of Lawsuit): In the Chamber’s decisions for the year 2024 (2024/9907, 2024/13609), it was explicitly stated that applying interest to the increased portions of an indeterminate claim lawsuit from the date of increase is erroneous, and that interest should be accrued on the entire claim from the date of the lawsuit.

Old/Different Approach (Date of Increase): In some of the Chamber’s decisions for the years 2019 and 2020 (2019/2925, 2020/2920K, 2020/5759), it was argued that even in cases of indeterminate claims (especially those with partial performance and full determination requests), interest should be applied according to the principles of a partial lawsuit and that interest should be accrued on the increased portion from the date of the request for increase. However, the 2024 decisions indicate that this view has been abandoned or that the date of the lawsuit is taken as the basis in current practice.

3. Situation Where the Case is Qualified as a “Partial Lawsuit” Even if the case is named “indeterminate claim lawsuit,” courts, if they conclude that it does not meet the conditions in terms of its nature and is actually a “partial lawsuit,” establish a different ruling regarding the commencement of interest.

Application: If the case is accepted as a partial lawsuit, interest is accrued on the amount stated in the petition from the date of the lawsuit, and on the increased (amended) portion from the date of amendment/increase.

Related Decisions:

Supreme Court 6th Civil Chamber (2025/1855): Although the case was filed as an uncertain receivable lawsuit, by accepting that it was in the nature of a partial lawsuit, it affirmed that interest should be applied to the increased portion from the date of amendment.

Supreme Court 22nd Civil Chamber (2018/1007): Due to the reservation of rights regarding the excess and the increase being made through amendment, it considered the case a partial lawsuit and stated that interest should be applied to the increased portion from the date of amendment.

Izmir 2nd Civil Commercial Court (2022/579K): On the grounds that the case was converted into an uncertain receivable lawsuit through amendment, it applied interest to the increased portion from the date of amendment.

4. Procedure and Timing of Interest Claim The start date of interest may also vary depending on when and how the interest claim was made.

If Interest Was Not Claimed in the Petition: In the decision of the Supreme Court 7th Civil Chamber (2016/11619), it was stated that if interest was not claimed in the original petition, it could not be claimed with an increase petition. However, in the decision of Istanbul 2nd Commercial Court (2022/691K), it was accepted that the interest claimed for the first time in the petition for an increased amount, rather than in the original petition, would commence from the date of the increased amount petition, not the date of the lawsuit.

If Requested in the Lawsuit Petition: In the decision of Konya 2nd Commercial Court of First Instance (2024/690K), it has been stated that even if interest is not explicitly written in the petition for value increase, the request for interest in the lawsuit petition and the nature of the lawsuit as an indeterminate claim case are sufficient for interest to accrue on the increased portion from the date of the lawsuit.

Conclusion When the presented court decisions are analyzed;

Provided that the lawsuit is a properly filed indeterminate claim case, it can be requested that interest accrues on the increased portion from the date of the lawsuit in the petition for value increase, and it is observed that courts (especially in line with current Supreme Court of Appeals and Regional Court of Appeals decisions, and the General Assembly of Civil Chambers decision) rule in this direction.

However, if the court qualifies the lawsuit as a partial lawsuit, it should not be forgotten that interest will accrue on the increased portion only from the date of increase (amendment). A paper suggestion.

Why is Expert Legal Counsel Necessary?

Technical distinctions such as the petition for an increase in claim amount in an uncertain claim lawsuit, the interest commencement date, and whether the lawsuit is a partial claim lawsuit or an uncertain claim lawsuit under Article 107 of the HMK; necessitate close follow-up of the current precedents of the Court of Cassation and Regional Courts of Justice. In practice, points such as determining the interest commencement date, qualifying the lawsuit, assessing default, the procedure for increasing the claim, and at which stage the interest claim will be valid, are critical factors directly affecting the outcome of the lawsuit.

In regions experiencing intense labor law disputes such as Istanbul, Tuzla, Pendik, Kartal, Maltepe, Kadıköy, Ataşehir, Ümraniye, Gebze, Dilovası, and Çayırova, even a minor procedural error in lawsuits concerning employee receivables can lead to the loss of a significant portion of the claim or insufficient application of interest. Especially when considering the periodic precedent changes of the 9th Civil Chamber of the Court of Cassation, the partial claim approaches of the 22nd Civil Chamber, and the binding decisions of the General Assembly of Civil Chambers, it is clear that this process requires expertise.

Therefore, 2M Law Firm aims to ensure that its clients receive their claims most effectively without suffering any loss of rights by providing professional legal support in technical matters such as employee receivables, uncertain claim lawsuits, claim increase, interest commencement, and the distinction between declaratory and performance actions. Expert legal support is critically important for the correct qualification of the lawsuit, the determination of whether the conditions of HMK Article 107 are met, the proper submission of interest claims, and the determination of a strategy in line with Court of Cassation precedents.