{
  "timeline": [
    {
      "date": "1958/12",
      "category": "会社設立",
      "region": "",
      "importance": 2,
      "event": "日窒電子化学を設立",
      "detail": "新日本窒素肥料が半導体用高純度シリコンの製造販売を目的に設立。三菱マテリアルシリコン系譜の起点",
      "significance": "日本の半導体用シリコン製造の黎明期に当たる前身会社の創業",
      "source": "有価証券報告書"
    },
    {
      "date": "1959/10",
      "category": "会社設立",
      "region": "",
      "importance": 2,
      "event": "日本電子金属を設立",
      "detail": "三菱金属鉱業等が半導体用高純度シリコンの製造販売を目的に設立。同社野田工場が同月生産開始",
      "significance": "三菱系シリコン事業の起点",
      "source": "有価証券報告書"
    },
    {
      "date": "1960/4",
      "category": "会社設立",
      "region": "",
      "importance": 2,
      "event": "小松電子金属を設立",
      "detail": "小松製作所と石塚研究所の共同出資。SUMCO TECHXIVの前身",
      "significance": "コマツ系シリコン事業の起点",
      "source": "有価証券報告書"
    },
    {
      "date": "1962/1",
      "category": "",
      "region": "",
      "importance": 2,
      "event": "シリコンウェーハ生産開始",
      "detail": "大阪チタニウム製造尼崎工場で生産開始。住友系シリコン事業の起点",
      "significance": "住友系シリコン事業の事業化スタート",
      "source": "有価証券報告書"
    },
    {
      "date": "1973/8",
      "category": "",
      "region": "",
      "importance": 1,
      "event": "九州電子金属を設立",
      "detail": "大阪チタニウム製造と住友金属工業の共同出資によるシリコンウェーハ製造会社",
      "significance": "",
      "source": "有価証券報告書"
    },
    {
      "date": "1991/10",
      "category": "組織再編",
      "region": "",
      "importance": 1,
      "event": "三菱マテリアルシリコンへ商号変更",
      "detail": "日本シリコンが三菱マテリアル傘下で商号変更",
      "significance": "",
      "source": "有価証券報告書"
    },
    {
      "date": "1992/10",
      "category": "組織再編",
      "region": "",
      "importance": 1,
      "event": "九州電子金属を吸収合併",
      "detail": "大阪チタニウム製造が吸収合併しシリコン事業を統合",
      "significance": "",
      "source": "有価証券報告書"
    },
    {
      "date": "1993/1",
      "category": "組織再編",
      "region": "",
      "importance": 1,
      "event": "住友シチックスへ商号変更",
      "detail": "大阪チタニウム製造が商号変更",
      "significance": "",
      "source": "有価証券報告書"
    },
    {
      "date": "1993/4",
      "category": "組織再編",
      "region": "",
      "importance": 1,
      "event": "コマツ電子金属へ商号変更",
      "detail": "小松電子金属が商号変更",
      "significance": "",
      "source": "有価証券報告書"
    },
    {
      "date": "1995/11",
      "category": "海外進出",
      "region": "中国",
      "importance": 1,
      "event": "FORMOSA KOMATSU SILICONを設立",
      "detail": "Formosa Plastics Groupとの共同出資による台湾の製造販売子会社（コマツ電子金属51%）",
      "significance": "",
      "source": "有価証券報告書"
    },
    {
      "date": "1997/9",
      "category": "株式上場",
      "region": "",
      "importance": 2,
      "event": "コマツ電子金属が東証二部上場",
      "detail": "後のSUMCO TECHXIVが上場",
      "significance": "SUMCOグループ前身企業の資本市場入り",
      "source": "有価証券報告書"
    },
    {
      "date": "1998/10",
      "category": "組織再編",
      "region": "",
      "importance": 2,
      "event": "住友金属工業がシチックス事業本部を発足",
      "detail": "住友金属工業と住友シチックスの合併によりシチックス事業本部が発足",
      "significance": "住友系シリコン事業の本社統合",
      "source": "有価証券報告書"
    },
    {
      "date": "1999/7",
      "category": "会社設立",
      "region": "",
      "importance": 3,
      "event": "シリコンユナイテッドマニュファクチュアリング設立",
      "detail": "住友金属工業・三菱マテリアル・三菱マテリアルシリコンの共同出資。SUMCOの直接の起点",
      "significance": "日本の住友系・三菱系シリコン事業統合の出発点で寡占構造形成の起点",
      "source": "有価証券報告書"
    },
    {
      "date": "2001/10",
      "category": "",
      "region": "",
      "importance": 3,
      "event": "300mmウェーハの生産開始",
      "detail": "",
      "significance": "世界的な300mm化トレンドにいち早く対応し業界2強の地位確立に直結",
      "source": "有価証券報告書"
    },
    {
      "date": "2002/1",
      "category": "海外進出",
      "region": "米州",
      "importance": 1,
      "event": "SUMCO USA Corporationを設立",
      "detail": "米国における持株会社",
      "significance": "",
      "source": "有価証券報告書"
    },
    {
      "date": "2002/2",
      "category": "組織再編",
      "region": "",
      "importance": 3,
      "event": "三菱住友シリコンへ商号変更",
      "detail": "住友金属工業からシチックス事業本部の営業を譲り受け、三菱マテリアルシリコンと合併",
      "significance": "住友系・三菱系シリコン事業の事業統合完了。SUMCOの実質的な事業母体形成",
      "source": "有価証券報告書"
    },
    {
      "date": "2005/8",
      "category": "組織再編",
      "region": "",
      "importance": 2,
      "event": "商号を株式会社SUMCOに変更",
      "detail": "",
      "significance": "グローバル展開を見据えたブランド統一",
      "source": "有価証券報告書"
    },
    {
      "date": "2005/11",
      "category": "株式上場",
      "region": "",
      "importance": 3,
      "event": "東証一部に上場",
      "detail": "",
      "significance": "事業統合からわずか3年での一部上場で資本調達基盤を確立",
      "source": "有価証券報告書"
    },
    {
      "date": "2006/1",
      "category": "社長交代",
      "region": "",
      "importance": 1,
      "event": "重松健二郎が代表取締役",
      "detail": "FY05時点で代表取締役を務める",
      "significance": "",
      "source": "有価証券報告書"
    },
    {
      "date": "2006/10",
      "category": "企業買収",
      "region": "",
      "importance": 3,
      "event": "コマツ電子金属を子会社化",
      "detail": "株式公開買付けにより子会社化。後のSUMCO TECHXIV。SUMCO Oregon Corporationは同月清算",
      "significance": "日系シリコンウェーハ業界の再編完了で信越化学とSUMCOの2強体制が確立",
      "source": "有価証券報告書"
    },
    {
      "date": "2007/1",
      "category": "組織再編",
      "region": "米州",
      "importance": 1,
      "event": "SUMCO USA Corporationを清算",
      "detail": "",
      "significance": "",
      "source": "有価証券報告書"
    },
    {
      "date": "2007/12",
      "category": "株式上場",
      "region": "中国",
      "importance": 2,
      "event": "FORMOSA SUMCO TECHNOLOGYが台湾上場",
      "detail": "台湾証券取引所に正式上場",
      "significance": "海外子会社の独自資本市場入り",
      "source": "有価証券報告書"
    },
    {
      "date": "2008/5",
      "category": "企業買収",
      "region": "",
      "importance": 2,
      "event": "SUMCO TECHXIVを完全子会社化",
      "detail": "株式交換の方法。同年8月に営業・技術部門を承継",
      "significance": "コマツ電子金属の完全統合でSUMCOグループ一体化完了",
      "source": "有価証券報告書"
    },
    {
      "date": "2009/6",
      "category": "社長交代",
      "region": "",
      "importance": 2,
      "event": "田口洋一が代表取締役に就任",
      "detail": "FY09に社長交代",
      "significance": "リーマンショック後の業績悪化局面での経営トップ交代",
      "source": "有価証券報告書"
    },
    {
      "date": "2010/1",
      "category": "",
      "region": "",
      "importance": 3,
      "event": "初の営業赤字・純損失を計上",
      "detail": "リーマンショック後の半導体市況急落を受け大幅赤字転落",
      "significance": "事業統合後初の大型赤字でシリコンウェーハ業界の市況脆弱性が露呈",
      "source": "有価証券報告書",
      "amount": "営業赤字▲865億円/純損失▲1004億円"
    },
    {
      "date": "2011/1",
      "category": "",
      "region": "",
      "importance": 2,
      "event": "2期連続赤字",
      "detail": "操業度低下と減損で赤字継続",
      "significance": "シリコンウェーハ需給悪化長期化局面",
      "source": "有価証券報告書",
      "amount": "営業赤字▲84億円/純損失▲655億円"
    },
    {
      "date": "2011/2",
      "category": "設備投資",
      "region": "",
      "importance": 2,
      "event": "尼崎工場閉鎖",
      "detail": "住友系の発祥拠点である尼崎工場を閉鎖",
      "significance": "シリコン事業の起点となった歴史的拠点の閉鎖でリストラを加速",
      "source": "有価証券報告書"
    },
    {
      "date": "2011/6",
      "category": "社長交代",
      "region": "",
      "importance": 2,
      "event": "橋本眞幸が代表取締役に就任",
      "detail": "FY11就任。後に長期にわたり経営を主導",
      "significance": "業績悪化期の体制再構築を担う長期政権の起点",
      "source": "有価証券報告書"
    },
    {
      "date": "2012/1",
      "category": "",
      "region": "",
      "importance": 2,
      "event": "3期連続純損失",
      "detail": "特別損失計上が継続",
      "significance": "構造改革の重い負担期",
      "source": "有価証券報告書",
      "amount": "純損失▲843億円"
    },
    {
      "date": "2012/11",
      "category": "組織再編",
      "region": "",
      "importance": 1,
      "event": "ジャパンスーパークォーツを吸収合併",
      "detail": "現JSQ事業部",
      "significance": "",
      "source": "有価証券報告書"
    },
    {
      "date": "2013/3",
      "category": "組織再編",
      "region": "",
      "importance": 1,
      "event": "SUMCOソーラーを清算",
      "detail": "",
      "significance": "",
      "source": "有価証券報告書"
    },
    {
      "date": "2013/7",
      "category": "設備投資",
      "region": "",
      "importance": 1,
      "event": "生野工場閉鎖",
      "detail": "",
      "significance": "小径ウェーハ事業のリストラ継続",
      "source": "有価証券報告書"
    },
    {
      "date": "2016/3",
      "category": "組織再編",
      "region": "",
      "importance": 1,
      "event": "監査等委員会設置会社に移行",
      "detail": "",
      "significance": "",
      "source": "有価証券報告書"
    },
    {
      "date": "2016/6",
      "category": "社長交代",
      "region": "",
      "importance": 2,
      "event": "橋本眞幸が代表取締役会長兼CEOに",
      "detail": "FY15末から会長兼CEOに就任し長期にわたり総括・市場環境を語る象徴的存在となる",
      "significance": "長期政権下での会長CEO体制移行",
      "source": "有価証券報告書"
    },
    {
      "date": "2022/4",
      "category": "組織再編",
      "region": "",
      "importance": 1,
      "event": "プライム市場へ移行",
      "detail": "東証市場区分見直しに伴う",
      "significance": "",
      "source": "有価証券報告書"
    },
    {
      "date": "2022/6",
      "category": "社長交代",
      "region": "",
      "importance": 2,
      "event": "阿波俊弘が社長に就任",
      "detail": "橋本会長兼CEO体制下で社長交代",
      "significance": "会長CEO橋本・社長阿波の二頭体制への移行",
      "source": ""
    },
    {
      "date": "2023/3",
      "category": "企業買収",
      "region": "",
      "importance": 2,
      "event": "高純度シリコン株式会社の株式取得",
      "detail": "三菱マテリアルが新設した高純度シリコンに半導体用多結晶シリコン事業等を承継させた上で同社株式を取得",
      "significance": "シリコン原料調達の垂直統合強化",
      "source": "有価証券報告書"
    },
    {
      "date": "2024/2",
      "category": "経営計画",
      "region": "",
      "importance": 1,
      "event": "FY23決算でAI需要下のウェーハ見通しを提示",
      "detail": "データセンター用先端ロジックウェーハ需要が23-27年CAGR26%・27年に23年比55%増を予測",
      "significance": "300mm先端品増強投資の継続方針を明示",
      "source": "IR",
      "amount": "設備投資3154億円"
    },
    {
      "date": "2025/2",
      "category": "構造改革",
      "region": "",
      "importance": 3,
      "event": "小径ウェーハ事業構造改革を発表",
      "detail": "SUMCO TECHXIV宮崎工場のウェーハ生産を2026年末に終了し200mmは長崎・伊万里へ、150mmはインドネシアへ移管。125mm他は生産終了。経営資源を300mm先端品に集中",
      "significance": "中国勢台頭と需要低迷に直面した小径事業の戦略撤退で300mm先端品集中を鮮明化",
      "source": "IR",
      "amount": "特別損失58億円(減損46億+棚卸評価減12億)"
    },
    {
      "date": "2025/12",
      "category": "",
      "region": "",
      "importance": 3,
      "event": "純損失に転落",
      "detail": "FY25営業利益13億円・純損失▲117億円。市況回復遅延と構造改革負担",
      "significance": "FY09以来の本格的な赤字転落",
      "source": "有価証券報告書",
      "amount": "営業利益13億円/純損失▲117億円"
    }
  ]
}