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S.BLOX Inc. — Japanese crypto-asset exchange operator overview

Confidence: Likely Updated 2026-05-18 Review by 2026-08-08 Sources 6 Machine-translated Original (JA)
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This entry sits under exchanges index. Read it with FSA crypto-asset exchange registration system — number system / Local Finance Bureau jurisdiction / registration requirements for adjacent context and Japan Financial Regulation — Legal Framework for Tokens, Crypto Assets, and Payments for the broader system boundary.

FSA registration number Kanto Local Finance Bureau 第00016号 · JVCEA member #1019 · registration date 2019-03-25

1. Corporate entity / shareholders

  • Trade name: S.BLOX Inc. (former trade names: Amber Japan, Inc.; DeCurret, Inc.)
  • English name: S.BLOX Inc.
  • Date established: 2018年1月10日
  • Head office location: 5-10号, Konan 2-chome, Minato-ku, Tokyo
  • Parent company: Quetta Web, Inc. (shareholding ratio 100%). Quetta Web is a subsidiary 100%-invested by Sony Group Corporation. The de facto ultimate parent is Sony Group Corporation (TSE Prime 6758).
  • Capital: 350,000,000円 (as of 2026年 per the official corporate site. As of 2024年7月 disclosure it was reported as 1,708,179,531円, and a capital reduction may have occurred since)
  • Listing: unlisted (the parent, Sony Group, is listed)

2. License / registration status

  • Crypto-asset exchange business: Director-General of the Kanto Local Finance Bureau 第00016号 (registration date 2019-03-25)
  • JVCEA member type: Type 1 member (membership number 1019). Crypto-asset exchange business only. No registration for crypto-asset derivatives business, electronic payment instruments business, or funds-transfer business (as of 2026-05-18).

3. Supported currencies

The brokerage (sales-outlet) coins listed on the official service site (as of 2026年5月) are the following 6:

  • BTC (Bitcoin)
  • ETH (Ethereum)
  • XRP (Ripple)
  • TRX (Tron)
  • BCH (Bitcoin Cash)
  • LTC (Litecoin)

The official site states that “further expansion is planned going forward.” BTC and ETH are major coins “traded domestically at 85% or more” (see the JVCEA FY 2022年 annual report). The altcoin lineup is at the industry’s smallest level, and at present the composition is centered on major currencies.

4. Scope of business

  • Spot trading (sales outlet): 6 coins such as BTC/ETH/XRP. Counterparty (spread) method.
  • Exchange (order-book trading): no public information (appears not offered as of 2026年5月).
  • Margin / derivatives: none (not registered for JVCEA crypto-asset derivatives business).
  • Fiat deposit channels: bank transfer. Deposit fees are announced as free after the service renewal. Details of quick deposit (convenience stores, etc.) are not disclosed.
  • NFT-related: conducted a Sony Group Soneium (blockchain) collaboration NFT campaign at 2025年 (Ghost in the Shell collaboration, etc.).
  • Minimum trade size: emphasizes support for small-lot investing. Lowered the minimum order quantity for bitcoin at 2026年3月.

5. Market share / trading volume

  • Number of accounts and monthly trading volume not disclosed (as of 2026年5月).
  • A small-scale operation with only 6 coins and brokerage-only, its industry position is classified as niche / small-scale. The scale gap versus major exchange operators such as bitFlyer, GMO Coin, and Coincheck is large.
  • After joining the Sony Group, it is seen to be exploring a user-acquisition strategy leveraging the parent’s brand power, but specific performance figures are not disclosed.

6. History / major events

  • 2018年1月: Established DeCurret, Inc. as an equity-method affiliate of Internet Initiative Japan Inc. (IIJ). Founded with a focus on digital-currency payment services.
  • 2019年3月: Crypto-asset exchange operator registration (Director-General of the Kanto Local Finance Bureau 第00016号). Began virtual-currency trading as the “DeCurret” service.
  • 2021年12月: Established DeCurret Holdings, Inc. and shifted to a holding-company structure.
  • 2022年2月: Succeeded the digital-currency business to DeCurret DCP, Inc. via an absorption-type split. On the same day, sold the remaining crypto-asset exchange business (exchange operation) portion to WhaleFin Holdings Japan, Inc., the Japanese entity of the Singapore-based market maker Amber Group (change of shareholder).
  • 2022年9月: Changed its company name to Amber Japan, Inc. The service name was also rebranded to “WhaleFin.”
  • 2023年8月: Quetta Web, Inc. (a subsidiary 100%-invested by Sony Group Corporation) acquired all shares of Amber Japan, joining the Sony Group. Lee Yijin, the Amber-era Representative Director, resigned, and Jun Watanabe, formerly of Sony Network Communications, became Representative Director and President.
  • 2024年7月1日: Changed its company name to S.BLOX Inc. Positioned as the crypto-asset exchange window in Sony Group’s Web 3 strategy.
  • 2025年1月: Completed the service renewal and changed the service name from “WhaleFin” to S.BLOX.

Regarding the relationship with TaoTao: TaoTao, Inc. (former Yahoo! Japan / Z Corp lineage) was merged into and absorbed by SBI VC Trade, Inc. at 2021年12月, and is a separate entity / separate lineage. It has no corporate-succession relationship whatsoever with S.BLOX (formerly DeCurret), and its FSA registration number differs.

7. Strategic developments

  • Soneium integration: publicly states integration with Soneium, a public blockchain developed by Sony Group as a joint venture of Sony Network Communications Labs and Startale Labs. As a crypto-asset exchange, it is expected to serve as the onramp function to NFTs and various Web 3 content.
  • NFT campaigns: continues to run collaborations with Sony Group’s IP and blockchain assets, such as the 2025年2月 “Ghost in the Shell NFT campaign” and the 2025年9月 “Soneium collaboration NFT campaign.”
  • Planned currency expansion: the official site previews the addition of more coins, but a specific timeline and coin names are undisclosed as of 2026年5月.
  • IPO developments: not disclosed. Operating as an unlisted subsidiary of its parent, the Sony Group.
  • Jun Watanabe (Representative Director and President): from Sony Network Communications. Reported to also serve concurrently as head of Sony G’s “Advanced Infrastructure Business Exploration Division” (Nikkei 2025年1月). Appointed upon completion of the 2023年8月 acquisition.
  • Lee Yijin (former representative): operated WhaleFin as the Japanese-entity representative of Amber Group. Resigned upon the 2023年8月 Sony acquisition.
  • IIJ (Internet Initiative Japan Inc.) (founding investor): the principal investor at DeCurret’s establishment. Has now exited from the shareholder roster.

Sources