diff --git a/arm_statements/amounts.py b/arm_statements/amounts.py
index 1c40eac..208eab6 100644
--- a/arm_statements/amounts.py
+++ b/arm_statements/amounts.py
@@ -88,8 +88,6 @@ def _split_core(core: str) -> tuple[str, SignForm, bool, bool] | None:
         fixed = core[-1] != ")"
         core = core[1:-1].strip()
         sign_form, negative = SignForm.PARENTHESES, True
-        if core and core[0] in "-−+":
-            core = core[1:].strip()
     elif core[0] in "-−+":
         if core[0] in _MINUSES:
             sign_form, negative = SignForm.MINUS, True
@@ -118,8 +116,6 @@ def _number(body: str, source: Source, text: str, sign_form: SignForm, *, negati
         return _guess(digits, text, sign_form, negative=negative)
     else:
         integer, fraction = compact.replace(",", ".").split(".")
-        if not integer:
-            return AmountParse(None, text, False, sign_form)
         if source is Source.OCR and len(fraction) >= 3:  # noqa: PLR2004 — три знака: не копейки
             return AmountParse(None, text, False, sign_form)
     if len(integer) > MAX_INTEGER_DIGITS:
@@ -181,9 +177,11 @@ def build_value(
     string_text = text if text.strip() else None
     value = cell.value
     if isinstance(value, Decimal):
-        amount = _quantize(value)
-        if _too_long(amount):
-            return ValueBuild(_plain(cell, column_index, AmountParse(None, text, False, None)), out_of_range=True)
+        # длину целой части проверяем до квантования: для 1E+30 и нефинитных значений quantize падает
+        amount = _quantize(value) if value.is_finite() and value.adjusted() < MAX_INTEGER_DIGITS else None
+        if amount is None or _too_long(amount):
+            overflow = AmountParse(None, string_text, False, None)
+            return ValueBuild(_plain(cell, column_index, overflow), out_of_range=True)
         return ValueBuild(
             _plain(cell, column_index, AmountParse(amount, None, True, None), recognized=not split_part),
             out_of_range=False,
diff --git a/arm_statements/tests/test_amounts.py b/arm_statements/tests/test_amounts.py
index 8025cf5..859880f 100644
--- a/arm_statements/tests/test_amounts.py
+++ b/arm_statements/tests/test_amounts.py
@@ -82,3 +82,38 @@ def test_build_value_date_missing_multiline_split(rules: Rules) -> None:
     assert (part.amount, part.is_recognized) == (D("917775"), False)
     dash = build_value(Cell("—", None, 100.0, "row:3"), 2, OCR, rules).value
     assert (dash.amount, dash.string_value, dash.is_recognized, dash.text) == (None, None, True, "—")
+
+
+@pytest.mark.parametrize("raw", ["1E+30", "Infinity", "NaN", "-Infinity", "10000000000000000"])
+def test_build_value_decimal_out_of_range(rules: Rules, raw: str) -> None:
+    built = build_value(Cell(raw, D(raw), 100.0, "Баланс!D1"), 3, EXCEL, rules)
+    assert (built.value.amount, built.value.string_value, built.value.is_recognized, built.out_of_range) == (
+        None,
+        raw,
+        False,
+        True,
+    )
+
+
+def test_build_value_decimal_empty_text_and_boundary(rules: Rules) -> None:
+    empty = build_value(Cell("", D("1E+30"), 100.0, "Баланс!D1"), 3, EXCEL, rules)
+    assert (empty.value.string_value, empty.out_of_range) == (None, True)
+    edge = build_value(Cell("x", D("9999999999999999"), 100.0, "Баланс!D1"), 3, EXCEL, rules)
+    assert (edge.value.amount, edge.out_of_range) == (D("9999999999999999"), False)
+    carry = build_value(Cell("x", D("9999999999999999.999"), 100.0, "Баланс!D1"), 3, EXCEL, rules)
+    assert (carry.value.amount, carry.out_of_range) == (None, True)
+
+
+def test_build_value_rounds_half_up(rules: Rules) -> None:
+    assert build_value(Cell("0,125", D("0.125"), 100.0, "Баланс!D1"), 3, EXCEL, rules).value.amount == D("0.13")
+    assert build_value(Cell("-0,125", D("-0.125"), 100.0, "Баланс!D1"), 3, EXCEL, rules).value.amount == D("-0.13")
+
+
+def test_sign_inside_parentheses_is_invalid(rules: Rules) -> None:
+    parsed = parse_amount("(-5)", OCR, rules)
+    assert (parsed.amount, parsed.string_value, parsed.is_recognized, parsed.sign_form) == (None, "(-5)", False, None)
+
+
+def test_leading_comma_is_edge_trash(rules: Rules) -> None:
+    parsed = parse_amount(",5", OCR, rules)
+    assert (parsed.amount, parsed.is_recognized) == (D("5"), False)