Press Releases

March 24, 2025

NTT DOCOMO Files Lawsuit Against Colt Technology Services for Refund of Overpaid Interconnection Charges

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TOKYO, JAPAN, March 24, 2025 --- NTT DOCOMO, INC. announced today that on March 24, 2025, it has filed a lawsuit with the Tokyo District Court against Colt Technology Services Co., Ltd. (“Colt”), a provider of voice interconnection services in Japan, seeking the reimbursement of overpaid interconnection charges. This follows the legally binding arbitration ruling issued by Japan’s Ministry of Internal Affairs and Communications (“MIC”) in July 2024 under Japan’s Telecommunications Business Act^*1.

Background

Since launching its "Kake ho-dai" unlimited calling plan in June 2014, DOCOMO has experienced a substantial increase in call traffic from its network to Colt’s network. Under standard industry practices, an increase in traffic volume should lead to a reduction in per-unit interconnection charges^*2. However, Colt maintained its charges at an elevated level instead of adjusting them downward, raising concerns for DOCOMO. Despite repeated requests for reasonable explanations and fair adjustments to reflect the increased volume of call traffic, negotiations failed to produce an agreement from fiscal year 2015 onward^*3.

During this period of non-agreement, DOCOMO continued making provisional payments to Colt based on the last agreed charge levels, under the assumption that these amounts would be reconciled upon reaching a final agreement.

In 2021, suspicions arose regarding potential traffic pumping^*4 activities involving Colt. Following this discovery, DOCOMO sought a detailed breakdown of traffic composition and interconnection charge calculations. However, Colt failed to provide satisfactory explanations. Given the lack of progress, DOCOMO determined that negotiations alone would not resolve the issue and formally applied for an arbitration ruling to the Minister for Internal Affairs and Communications in January 2023.

Arbitration Ruling and DOCOMO’s Position

In July 2024, the MIC issued a binding arbitration ruling confirming the appropriate interconnection charge levels. The arbitration process, conducted in accordance with Japan’s Telecommunications Business Act and MIC’s “Guidelines on Amounts to be Obtained or Borne Regarding Interconnection,” ^*5 established a legally binding agreement between DOCOMO and Colt regarding interconnection charges.

The arbitration ruling determined that the appropriate interconnection charge levels were significantly lower than the provisional rates DOCOMO had been paying over the years of non-agreement. As a result, it was confirmed that DOCOMO had been overpaying for nearly a decade, dating back to 2015. The overpaid amounts, now determined based on the arbitration ruling, must be refunded to DOCOMO, and Colt is legally obligated to comply.

Following the arbitration ruling, DOCOMO engaged in multiple discussions with Colt to facilitate the refund process. However, Colt has consistently refused to comply, leaving DOCOMO with no alternative but to seek judicial enforcement through the courts.

Next Steps

DOCOMO remains committed to ensuring compliance with the arbitration decision and will pursue all necessary judicial measures to recover the overpaid amounts.

1. For details, please refer to “Ruling on an Application from NTT DOCOMO, INC. pursuant to Article 35, Paragraph 3 of the Telecommunications Business Act”
2. Refers to the amount paid by DOCOMO to Colt for the connection between DOCOMO's telecommunications facilities and Colt's telecommunications facilities.
3. DOCOMO’s fiscal year runs from April 1 to 31 March of the following year. However, only the ISDN category for fiscal year 2015 has agreed-upon interconnection charges.
4. Intentional increase in traffic volume through the establishment of incoming call incentive agreements, thereby boosting revenue from interconnection charges. For details, please refer to “Guidelines for Applying Business Improvement Orders to Incoming Incentive Contracts that Cause Traffic Pumping"
5. For details, please refer to “Formulation of Arbitrage Policy on Amounts to be Acquired/Shouldered for Interconnection”