diff --git a/backend/app/api/reports.py b/backend/app/api/reports.py
index 5f64fa63..5fedd5a0 100644
--- a/backend/app/api/reports.py
+++ b/backend/app/api/reports.py
@@ -2414,11 +2414,15 @@ def get_dupont_analysis(
     roe_exact = f_ann.get("roe")
     roe_change = None if (roe_exact is None or prev_roe is None) else round(roe_exact - prev_roe, 4)
 
+    def _fmt(v):
+        # 存量/流量缺失时 raw 值为 None（如博海存量仅到区间外）⇒ 显式「-」，不得 None 格式化
+        return "-" if v is None else f"{v:.2f}"
+
     detail = (f"{label}口径（流量累计 {win['period_start']}~{win['period_end']}，"
               f"存量{'平均' if cur['basis'] == 'average' else '期末回落'}"
               f"{'，年化 ×12/' + str(win['months']) if annualize else '，非年化'}）："
-              f"净利润 {cur['raw']['net_profit']:.2f}万 / 营业收入 {cur['raw']['revenue']:.2f}万 / "
-              f"平均总资产 {cur['raw']['total_assets']:.2f}万 / 平均净资产 {cur['raw']['equity']:.2f}万；"
+              f"净利润 {_fmt(cur['raw']['net_profit'])}万 / 营业收入 {_fmt(cur['raw']['revenue'])}万 / "
+              f"平均总资产 {_fmt(cur['raw']['total_assets'])}万 / 平均净资产 {_fmt(cur['raw']['equity'])}万；"
               f"ROE = {factors['net_profit_margin']['value']}% × {factors['asset_turnover']['value']} × "
               f"{factors['equity_multiplier']['value']} = {None if roe_exact is None else round(roe_exact, 2)}%"
               f"（恒等式 {'通过' if identity.get('status') == 'pass' else identity.get('status')}，"