{
  "timeline": [
    {
      "date": "1901/7",
      "category": "会社設立",
      "region": "",
      "importance": 3,
      "event": "光永星郎が日本広告株式会社を設立",
      "detail": "資本金10万円で東京にて創業",
      "significance": "電通グループの起源、明治期広告業の黎明",
      "source": "有価証券報告書",
      "amount": "資本金10万円"
    },
    {
      "date": "1901/11",
      "category": "組織再編",
      "region": "",
      "importance": 2,
      "event": "電報通信社を併設し通信社業務を開始",
      "detail": "日本広告社屋内に併設",
      "significance": "広告と通信の二本柱を初期から確立、後の総合情報企業の原型",
      "source": "有価証券報告書"
    },
    {
      "date": "1906/12",
      "category": "組織再編",
      "region": "",
      "importance": 2,
      "event": "株式会社日本電報通信社を設立",
      "detail": "旧電報通信社の事業を継承",
      "significance": "法人化と同時に通信業務を再構築",
      "source": "有価証券報告書"
    },
    {
      "date": "1907/8",
      "category": "組織再編",
      "region": "",
      "importance": 2,
      "event": "日本広告株式会社を合併し通信・広告を一体化",
      "detail": "資本金を26万円に増資",
      "significance": "広告・通信の二事業を1社に統合、広告通信複合企業体の確立",
      "source": "有価証券報告書",
      "amount": "資本金26万円"
    },
    {
      "date": "1936/6",
      "category": "組織再編",
      "region": "",
      "importance": 3,
      "event": "通信部を同盟通信社へ移管、聯合通信社広告部を吸収",
      "detail": "通信統制下で広告取扱専業へ転換",
      "significance": "国策通信統制で通信事業を喪失、広告専業企業として再出発した転機",
      "source": "有価証券報告書",
      "amount": "資本金200万円"
    },
    {
      "date": "1955/7",
      "category": "組織再編",
      "region": "",
      "importance": 2,
      "event": "商号を株式会社電通に変更",
      "detail": "",
      "significance": "戦後復興期に「電通」ブランドを確立",
      "source": "有価証券報告書"
    },
    {
      "date": "1967/7",
      "category": "組織再編",
      "region": "",
      "importance": 1,
      "event": "本店を中央区築地に移転",
      "detail": "",
      "significance": "",
      "source": ""
    },
    {
      "date": "1975/12",
      "category": "",
      "region": "",
      "importance": 2,
      "event": "株式会社電通国際情報サービス（ISID）を設立",
      "detail": "",
      "significance": "広告以外の情報サービス領域への足場を確保",
      "source": "有価証券報告書"
    },
    {
      "date": "1994/12",
      "category": "組織再編",
      "region": "",
      "importance": 1,
      "event": "地域電通5社（東日本・西日本・九州・北海道・東北）を設立",
      "detail": "",
      "significance": "全国営業網の子会社化",
      "source": "有価証券報告書"
    },
    {
      "date": "1996/4",
      "category": "組織再編",
      "region": "",
      "importance": 1,
      "event": "電通アクティス等4社を統合し電通テックを発足",
      "detail": "",
      "significance": "プロモーション領域の集約",
      "source": "有価証券報告書"
    },
    {
      "date": "2000/11",
      "category": "株式上場",
      "region": "",
      "importance": 2,
      "event": "電通国際情報サービス（ISID）が東証一部に上場",
      "detail": "",
      "significance": "子会社の上場で情報サービス事業の市場評価を得る",
      "source": "有価証券報告書"
    },
    {
      "date": "2001/11",
      "category": "株式上場",
      "region": "",
      "importance": 3,
      "event": "電通本体が東京証券取引所市場第一部に上場",
      "detail": "資本金を589億6,710万円に増資",
      "significance": "100年企業が満を持して株式公開、広告業界初のメガ上場",
      "source": "有価証券報告書",
      "amount": "資本金589億円"
    },
    {
      "date": "2002/11",
      "category": "組織再編",
      "region": "",
      "importance": 1,
      "event": "本店を港区東新橋（汐留）に移転",
      "detail": "汐留新本社ビル",
      "significance": "",
      "source": ""
    },
    {
      "date": "2009/1",
      "category": "組織再編",
      "region": "",
      "importance": 1,
      "event": "株券電子化に伴い株式分割（1:100）",
      "detail": "",
      "significance": "",
      "source": ""
    },
    {
      "date": "2010/6",
      "category": "社長交代",
      "region": "",
      "importance": 2,
      "event": "髙嶋達佳から石井直へ社長交代",
      "detail": "",
      "significance": "アジア・グローバル展開を本格化させる体制へ",
      "source": "有価証券報告書"
    },
    {
      "date": "2013/3",
      "category": "企業買収",
      "region": "欧州",
      "importance": 4,
      "event": "英国Aegis Group plcを完全子会社化",
      "detail": "スキーム・オブ・アレンジメントで全株取得、Dentsu Aegis Network Ltd.に商号変更",
      "significance": "日本の広告会社による史上最大級のクロスボーダー買収、グローバル・メガ・エージェンシー化の決定打",
      "source": "有価証券報告書",
      "amount": "株式取得額約4,000億円規模"
    },
    {
      "date": "2013/7",
      "category": "組織再編",
      "region": "",
      "importance": 1,
      "event": "資本金を712億470万円に増資",
      "detail": "",
      "significance": "",
      "source": ""
    },
    {
      "date": "2013/8",
      "category": "組織再編",
      "region": "",
      "importance": 1,
      "event": "資本金を746億981万円に増資",
      "detail": "",
      "significance": "",
      "source": ""
    },
    {
      "date": "2016/3",
      "category": "組織再編",
      "region": "",
      "importance": 1,
      "event": "監査役会設置会社から監査等委員会設置会社へ移行",
      "detail": "",
      "significance": "ガバナンス体制の改編",
      "source": "有価証券報告書"
    },
    {
      "date": "2016/6",
      "category": "社長交代",
      "region": "",
      "importance": 2,
      "event": "石井直から山本敏博へ社長交代",
      "detail": "新入社員過労自殺事件後の労務改革下での交代",
      "significance": "コンプライアンス危機後の経営刷新",
      "source": "有価証券報告書"
    },
    {
      "date": "2016/7",
      "category": "",
      "region": "",
      "importance": 2,
      "event": "株式会社電通デジタルを設立",
      "detail": "",
      "significance": "国内デジタル広告事業の専業会社化",
      "source": "有価証券報告書"
    },
    {
      "date": "2016/9",
      "category": "企業買収",
      "region": "米州",
      "importance": 4,
      "event": "米国Merkle Group Inc.を買収",
      "detail": "CRM・データマーケティング大手",
      "significance": "データドリブンマーケティング能力を獲得、CT&T戦略の中核",
      "source": "有価証券報告書"
    },
    {
      "date": "2017/1",
      "category": "組織再編",
      "region": "",
      "importance": 1,
      "event": "電通テックを電通ライブに改組改称、新たに電通テックを設立",
      "detail": "プロモーション領域再編",
      "significance": "",
      "source": ""
    },
    {
      "date": "2019/1",
      "category": "企業買収",
      "region": "",
      "importance": 2,
      "event": "株式会社CARTA HOLDINGS（旧VOYAGE GROUP）を株式交換で子会社化",
      "detail": "",
      "significance": "アドテク・メディア領域の取り込み",
      "source": "有価証券報告書"
    },
    {
      "date": "2019/12",
      "category": "",
      "region": "",
      "importance": 3,
      "event": "海外事業を中心にのれん減損、初の営業赤字",
      "detail": "営業損失▲33億円、最終損失▲808億円",
      "significance": "Aegis買収後の海外戦略が初めて機能不全を露呈",
      "source": "有価証券報告書",
      "amount": "営業損失▲33億円"
    },
    {
      "date": "2020/1",
      "category": "組織再編",
      "region": "",
      "importance": 4,
      "event": "純粋持株会社体制へ移行、株式会社電通グループに商号変更",
      "detail": "会社分割で広告事業を新電通に承継",
      "significance": "100年以上の事業会社体制を終え、グループ経営に転換した抜本改革",
      "source": "有価証券報告書"
    },
    {
      "date": "2020/4",
      "category": "企業買収",
      "region": "米州",
      "importance": 2,
      "event": "米国Merkle Group Inc.を完全子会社化",
      "detail": "",
      "significance": "CT&T戦略の中核子会社の100%化",
      "source": "有価証券報告書"
    },
    {
      "date": "2020/9",
      "category": "",
      "region": "",
      "importance": 1,
      "event": "Dentsu Aegis Network Ltd.をDentsu International Limitedに商号変更",
      "detail": "",
      "significance": "海外ブランドを「Dentsu International」に統一",
      "source": "有価証券報告書"
    },
    {
      "date": "2020/12",
      "category": "",
      "region": "",
      "importance": 3,
      "event": "コロナ禍で過去最大の最終赤字、海外のれん大型減損",
      "detail": "営業損失▲1,406億円、最終損失▲1,596億円、構造改革断行",
      "significance": "Aegis買収以降の海外不振がコロナ禍で一気に表面化、構造改革決断の引き金",
      "source": "有価証券報告書",
      "amount": "最終損失▲1,596億円"
    },
    {
      "date": "2021/12",
      "category": "",
      "region": "",
      "importance": 3,
      "event": "V字回復で過去最高の売上総利益・調整後営業利益",
      "detail": "売上総利益9,765億円、調整後営業利益1,790億円",
      "significance": "構造改革とコロナ反動需要が重なり最高益更新、五十嵐就任前の追い風",
      "source": "IR",
      "amount": "調整後営業利益1,790億円"
    },
    {
      "date": "2022/1",
      "category": "組織再編",
      "region": "",
      "importance": 1,
      "event": "電通コーポレートワンが事業開始",
      "detail": "電通ジャパンネットワークのコーポレート機能を集約",
      "significance": "",
      "source": "有価証券報告書"
    },
    {
      "date": "2022/1",
      "category": "企業買収",
      "region": "",
      "importance": 2,
      "event": "セプテーニ・ホールディングスを連結子会社化",
      "detail": "株式追加取得",
      "significance": "デジタルマーケティング資産の取り込み",
      "source": "有価証券報告書"
    },
    {
      "date": "2022/4",
      "category": "",
      "region": "",
      "importance": 1,
      "event": "電通テックを電通プロモーションプラスに商号変更",
      "detail": "",
      "significance": "",
      "source": ""
    },
    {
      "date": "2022/6",
      "category": "社長交代",
      "region": "",
      "importance": 2,
      "event": "山本敏博から五十嵐博へ社長交代",
      "detail": "Dentsu International CEO経験者の登板",
      "significance": "海外不振局面でグローバルCEO経験者を起用",
      "source": "有価証券報告書"
    },
    {
      "date": "2023/3",
      "category": "組織再編",
      "region": "",
      "importance": 2,
      "event": "監査等委員会設置会社から指名委員会等設置会社へ移行",
      "detail": "",
      "significance": "グローバル基準のガバナンス体制を導入",
      "source": "有価証券報告書"
    },
    {
      "date": "2023/3",
      "category": "企業買収",
      "region": "欧州",
      "importance": 3,
      "event": "英国Tag Worldwide Holdings Ltd.を買収",
      "detail": "コンテンツ制作大手",
      "significance": "M&A偏重路線終盤の大型案件、後の見直し対象となる",
      "source": "有価証券報告書"
    },
    {
      "date": "2024/1",
      "category": "",
      "region": "",
      "importance": 1,
      "event": "電通国際情報サービスを電通総研に商号変更",
      "detail": "",
      "significance": "",
      "source": ""
    },
    {
      "date": "2024/7",
      "category": "事業売却",
      "region": "欧州",
      "importance": 3,
      "event": "ロシア事業を現地パートナーに譲渡し撤退完了",
      "detail": "2022年11月締結の譲渡契約が国際制裁準拠確認後に完了",
      "significance": "ウクライナ侵攻後の地政学リスク資産整理",
      "source": "IR"
    },
    {
      "date": "2024/12",
      "category": "",
      "region": "",
      "importance": 4,
      "event": "海外のれん2,101億円減損、最終赤字▲1,921億円",
      "detail": "減損損失2,352億円、営業損失▲1,249億円、構造改革費用107億円",
      "significance": "Aegis-Merkle路線の収益限界が顕在化、中計再策定の引き金",
      "source": "IR",
      "amount": "最終損失▲1,921億円"
    },
    {
      "date": "2025/2",
      "category": "経営計画",
      "region": "",
      "importance": 3,
      "event": "中期経営計画2025-2027を策定、M&A偏重路線を公式に否定",
      "detail": "オーガニック成長回帰、ポートフォリオ見直し、One dentsu",
      "significance": "自社のM&A戦略を否定し成長軌道へのリセットを宣言した転機",
      "source": "IR",
      "amount": "内部投資450億円・一時費用500億円"
    },
    {
      "date": "2025/12",
      "category": "",
      "region": "",
      "importance": 5,
      "event": "2年連続の巨額減損で最終赤字▲3,276億円、上場後初の無配に転落",
      "detail": "減損4,025億円（Americas2,996億円・EMEA964億円）、構造改革費用330億円",
      "significance": "海外事業の収益回復シナリオ崩壊、成長戦略の再構築が不可避となる経営危機",
      "source": "IR",
      "amount": "最終損失▲3,276億円、配当0円"
    },
    {
      "date": "2026/1",
      "category": "組織再編",
      "region": "",
      "importance": 1,
      "event": "電通プロモーションプラス等4社を統合し電通プロモーションに商号変更",
      "detail": "",
      "significance": "プロモーション領域の再集約",
      "source": "有価証券報告書"
    }
  ]
}