Custody Bank of Japan (CBJ)

Wiki route

This entry sits under trust-banks INDEX. Read it against Master Trust Bank for peer / contrast context and banking index for the broader system / regulatory boundary.

TL;DR

Japan’s largest-class trust-custody specialist bank (trust assets total approximately 476 兆円, assets under custody including account-administration business approximately 696 兆円, both as of end 2025-03 ). Established 2020-07-27 through the merger of Japan Trustee Services Bank (JTSB) + Trust & Custody Services Bank (TCSB). A joint venture of sumitomo-mitsui-trust (Sumitomo Mitsui Trust Group) 33.3% + mizuho-fg 27.0% + Resona Bank 16.7% + dai-ichi-life Dai-ichi Life 8.0% + Asahi Mutual Life 5.0% + Meiji Yasuda Life 4.5% + Japan Post Insurance 3.5% + Fukoku Mutual Life 2.0% (as of 2020-07-27). Appears as a regular fixture in the major-shareholder columns of listed companies as “Custody Bank of Japan (trust account)” ★. Together with The Master Trust Bank of Japan master-trust-bank (MUFG mufg + nippon-life affiliated), it forms the domestic 2 leaders among trust-account shareholders (a 2 -leader structure in securities custody).

1. Company overview

Formal name: Custody Bank of Japan, Ltd. English name: Custody Bank of Japan, Ltd. (CBJ) Established: 2020-07-27 (formed through the merger of JTSB + TCSB) Business type: Trust-custody specialist bank (trust banking / Banking Act + Trust Business Act) Listing: Unlisted (joint venture, funded by multiple trust FGs) Head office: Harumi Island Triton Square Office Tower Z, 1-8-12 Harumi, Chuo-ku, Tokyo

Major shareholders (public materials, as of 2020-07-27)

Shareholder	Stake
sumitomo-mitsui-trust (Sumitomo Mitsui Trust Group)	33.3%
mizuho-fg (Mizuho Financial Group)	27.0%
Resona Bank	16.7%
dai-ichi-life Dai-ichi Life Insurance	8.0%
Asahi Mutual Life Insurance	5.0%
Meiji Yasuda Life Insurance	4.5%
Japan Post Insurance	3.5%
Fukoku Mutual Life Insurance	2.0%

Importance ★

Appears in the major-shareholder columns of nearly all listed companies in Japan as “Custody Bank of Japan (trust account)”
Together with The Master Trust Bank of Japan master-trust-bank, one of the 2 leaders among “trust-account shareholders”
Trust assets total approximately 476 兆円, assets under custody including account-administration business approximately 696 兆円 (both as of end 2025-03 , CBJ disclosure report 2025)
One arm of the central custody / administration institution for domestic pensions (employees’ pension / private pensions / defined-contribution pensions, etc.)

Merger history / predecessors

JTSB lineage (former SuMi TRUST lineage)
  Japan Trustee Services Bank (established 2000 )
    ├── former Chuo Mitsui Trust Bank (→ SuMi TRUST [[trust-banks/sumitomo-mitsui-trust]])
    ├── former Sumitomo Trust Bank (→ SuMi TRUST [[trust-banks/sumitomo-mitsui-trust]])
    └── Dai-ichi Life [[life-insurers/dai-ichi-life]] etc.

TCSB lineage (former Mizuho + Resona lineage)
  Trust & Custody Services Bank (established 2004 )
    ├── Mizuho Trust Bank ([[megabanks/mizuho-fg]])
    ├── Resona Bank (former Daiwa / Asahi trust lineage)
    ├── Asahi Mutual Life / Meiji Yasuda Life / Japan Post Insurance / Fukoku Mutual Life etc.
    └── former Dai-ichi Kangyo Fuji Trust / Yasuda Trust lineage

  ↓ 2020-07-27 merger

Custody Bank of Japan (CBJ)
  ├── Sumitomo Mitsui Trust Group [[trust-banks/sumitomo-mitsui-trust]] 33.3%
  ├── Mizuho FG [[megabanks/mizuho-fg]] 27.0%
  ├── Resona Bank 16.7%
  ├── Dai-ichi Life [[life-insurers/dai-ichi-life]] 8.0%
  └── Asahi Mutual Life 5.0% / Meiji Yasuda Life 4.5% / Japan Post Insurance 3.5% / Fukoku Mutual Life 2.0%

2. Business segment map

Segment	Main business	Features
Trust custody	Custody of listed stocks, bonds, investment trusts	Voting-rights exercise under trust-account name
Pension trust	Employees’ pension funds, defined-benefit corporate pensions, defined-contribution pensions	Trust acceptance, performance reporting, benefit administration
Investment-trust trusteeship	Trust agreements for public / private investment trusts	Custody / calculation for Investment Trusts Association member funds
Specified money trust (tokkin)	Investment vehicles for institutional investors / business corporations	Acceptance / administration
Asset administration services	Master Custody for institutional investors	Investment-instruction acceptance / performance reporting

Specialist position

Trust custody + pension trust specialist: holds no commercial-banking business, securities business, or retail
A division of labor in which the parents SuMi TRUST sumitomo-mitsui-trust / Mizuho Trust mizuho-fg are the front office (management / sales), and CBJ is the back office (custody / calculation / administration)

Competition / domestic 2 -leader structure

The Master Trust Bank of Japan master-trust-bank (MUFG mufg + nippon-life Nippon Life affiliated): largest competitor
Japan’s securities custody / trust-account shareholders form a 2 -leader structure of CBJ + Master Trust
The two effectively oligopolize the custody back office for Japan’s institutional-investor / pension assets

Influence as a trust-account shareholder

Appears in listed companies’ major-shareholder columns as “Custody Bank of Japan (trust account)”
Voting-rights exercise as a rule follows the management institution (the instructions of the trust-principal owner) (CBJ itself does not exercise voting rights independently)

Integration synergies

Main purpose of the JTSB + TCSB merger (2020-07): systems integration, scale effects, operating-cost reduction
Unification at CBJ of the custody systems / investment-trust calculation systems that had been duplicated by parent

4. Regulation / policy

Supervisor: Financial Services Agency (FSA)
Legal positioning: Banking Act + Trust Business Act (concurrent trust operation)
Deposit insurance: Member of the Deposit Insurance Corporation (as a trust-custody specialist, deposits for general depositors are limited)
Indirect regulation: Trust Companies Association / Investment Trusts Association / Japan Securities Dealers Association
Recent policy issues:
- 2024~ NISA expansion → increase in investment-trust assets under custody
- 2025~ defined-contribution pension system reform (contribution-limit expansion) → upward pressure on trust assets

5. Key chronology

Year/Month	Event
2000	Japan Trustee Services Bank (JTSB) established (former Chuo Mitsui Trust + Sumitomo Trust + Dai-ichi Life, etc.)
2004	Trust & Custody Services Bank (TCSB) established (Mizuho lineage + Asahi Mutual Life + Fukoku Mutual Life, etc.)
2011-04	Chuo Mitsui Trust + Sumitomo Trust → Sumitomo Mitsui Trust HD sumitomo-mitsui-trust formed → JTSB parent integration
2020-07-27	JTSB + TCSB merger → Custody Bank of Japan (CBJ) formed ★
2024	Medium-term plan (specific contents not disclosed in IR)

master-trust-bank · sumitomo-mitsui-trust · mizuho-fg · dai-ichi-life
Resona Bank (CBJ 3 位-largest shareholder 16.7%)
mufg · nippon-life (Master Trust side)
Related wiki: trust banking / custody / trust-account shareholders / voting-rights exercise

Sources

Wikipedia: 株式会社日本カストディ銀行 https://ja.wikipedia.org/wiki/日本カストディ銀行 — shareholder composition (as of 2020-07-27): Sumitomo Mitsui Trust Group 33.3% / Mizuho FG 27.0% / Resona Bank 16.7% / Dai-ichi Life 8.0% / Asahi Mutual Life 5.0% / Meiji Yasuda Life 4.5% / Japan Post Insurance 3.5% / Fukoku Mutual Life 2.0% (2026-05-30 confirmed. Corrected the old version’s “SMTB 46.5% / Mizuho 27% / Dai-ichi Life 8%”)
Wikipedia: 日本トラスティ・サービス信託銀行 (JTSB) (2026-05-19 extracted)
Wikipedia: 資産管理サービス信託銀行 (TCSB) (2026-05-19 extracted)
Sumitomo Mitsui Trust Bank: Pursuit of scale merits (Custody Bank of Japan’s trust assets total 476 兆円 / assets under custody including account administration 696 兆円, as of end 2025-03 ) https://www.smtb.jp/business/instrument/management/scale
Custody Bank of Japan: disclosure report 2025 (trust assets total 476 兆円, end 2025-03 ) https://www.custody.jp/data/disclosure/pdf/disclosure202507.pdf
Parent IR disclosures (sumitomo-mitsui-trust / mizuho-fg / dai-ichi-life)

[!info] Verification status confidence: likely (v1.0 Wikipedia + public IR verification 2026-05-19; 2026-05-29 trust assets confirmed against source; 2026-05-30 shareholder composition corrected). Correction point (2026-05-30): the old version’s funding ratios “SMTB 46.5% / Mizuho 27.0% / Dai-ichi Life 8.0%” are wrong (46.5% was an erroneous transcription of MUFG Trust’s ratio in The Master Trust Bank of Japan). The correct CBJ shareholder composition (as of 2020-07-27) is Sumitomo Mitsui Trust Group 33.3% / Mizuho FG 27.0% / Resona Bank 16.7% / Dai-ichi Life 8.0% / Asahi Mutual Life 5.0% / Meiji Yasuda Life 4.5% / Japan Post Insurance 3.5% / Fukoku Mutual Life 2.0% (consistently confirmed across Wikipedia + multiple secondary sources). The establishment date (2020-07-27) is based on public materials. The scale of assets under custody is confirmed via the CBJ disclosure report 2025 (through the Sumitomo Mitsui Trust Bank site): trust assets total approximately 476 兆円 / assets under custody including account-administration business approximately 696 兆円 (both as of end 2025-03 ). Specific trusteeship shares / quantitative results of integration synergies are not disclosed, so they are separated into Open questions / isolation.