diff --git a/synthgen/osv.py b/synthgen/osv.py
index cc180f2..e1827ea 100644
--- a/synthgen/osv.py
+++ b/synthgen/osv.py
@@ -32,6 +32,7 @@ from synthgen.periods import Period
 ZERO = Decimal(0)
 STYLE_PATH = Path(__file__).with_name("templates") / "osv_style.json"
 SHEET = "Лист_1"
+AMOUNT_FORMAT = "#,##0.00"
 Six = tuple[Decimal, Decimal, Decimal, Decimal, Decimal, Decimal]
 
 
@@ -304,6 +305,10 @@ def write(path: Path, member: Member, account: str, period: Period, data: list[O
         for c, value in row["values"].items():
             ws.cell(i, col(int(c)), placeholders.get(value, value))
     if with_inn:
+        # шапка колонки ИНН оформлена как соседняя шапка «Сальдо на начало периода» (заливка, рамки, Arial 9)
+        first_sum = tpl["sum_spans"][0][0]
+        for i in (9, 10, 11):
+            _apply(ws.cell(i, inn_col), st.get(f"header{i}", first_sum))
         ws.cell(10, inn_col, "ИНН")
     for r1, c1, r2, c2 in tpl["header_merges"]:
         ws.merge_cells(start_row=r1, start_column=col(c1), end_row=r2, end_column=col(c2))
@@ -315,7 +320,8 @@ def write(path: Path, member: Member, account: str, period: Period, data: list[O
     def put_sums(r: int, six: Six) -> None:
         for (a, b), value in zip(spans, six, strict=True):
             if value != 0:
-                ws.cell(r, a, float(value))
+                # формат задаём явно: в строке-образце сальдо бывает пустым, и его ячейка несёт «Общий» формат
+                ws.cell(r, a, float(value)).number_format = AMOUNT_FORMAT
                 if b > a:
                     ws.merge_cells(start_row=r, start_column=a, end_row=r, end_column=b)
 
diff --git a/synthgen/tests/test_osv.py b/synthgen/tests/test_osv.py
index 222fbf9..7a15eef 100644
--- a/synthgen/tests/test_osv.py
+++ b/synthgen/tests/test_osv.py
@@ -63,6 +63,25 @@ def test_style_matches_sample(tmp_path, osv_world):
     assert number.number_format == "#,##0.00"
 
 
+@pytest.mark.parametrize("inn", [False, True])
+def test_every_amount_has_number_format(tmp_path, osv_world, inn):
+    """Все суммы (сальдо и обороты, строки счёта, субсчёта, контрагента, «Итого») — `#,##0.00`, как в 1С."""
+    for account in ("60", "62", "76"):
+        (tmp_path / account).mkdir()
+        ws, *_ = _write(tmp_path / account, osv_world, account, inn=inn)
+        bad = [c.coordinate for row in ws.iter_rows(min_row=12) for c in row
+               if isinstance(c.value, (int, float)) and c.number_format != "#,##0.00"]
+        assert not bad, (account, bad[:10])
+
+
+def test_inn_header_styled_like_header(tmp_path, osv_world):
+    ws, *_ = _write(tmp_path, osv_world, "60", inn=True)
+    for r in (9, 10):  # E10:E11 объединена — вид задаёт верхняя ячейка
+        assert ws.cell(r, 5).fill.fgColor.rgb == ws.cell(r, 1).fill.fgColor.rgb == "FFF4ECC5", r
+        assert ws.cell(r, 5).border.left.style and ws.cell(r, 5).border.top.style, r
+    assert ws["E10"].font.name == "Arial" and ws["E10"].font.sz == 9
+
+
 def test_merges_follow_sample(tmp_path, osv_world):
     ws, *_ = _write(tmp_path, osv_world, "62", inn=False)
     got = {str(m) for m in ws.merged_cells.ranges if m.min_row in (9, 10, 11)}