diff --git a/src/builtins/core/duration.rs b/src/builtins/core/duration.rs
index afc78cb90..aa59bda8f 100644
--- a/src/builtins/core/duration.rs
+++ b/src/builtins/core/duration.rs
@@ -181,27 +181,26 @@ impl Duration {
             duration_record.normalized_time_duration(),
             largest_unit,
         )?;
-        Self::new(
-            duration_record.date().years.into(),
-            duration_record.date().months.into(),
-            duration_record.date().weeks.into(),
+        let sign = duration_record.sign()?;
+        let mut duration = Self::new(
+            i64::from(duration_record.date().years),
+            i64::from(duration_record.date().months),
+            i64::from(duration_record.date().weeks),
             i64::try_from(duration_record.date().days)
                 .or(Err(TemporalError::range()))?
                 .checked_add(overflow_day)
                 .ok_or(TemporalError::range())?,
-            time.hours.try_into().or(Err(TemporalError::range()))?,
-            time.minutes.try_into().or(Err(TemporalError::range()))?,
-            time.seconds.try_into().or(Err(TemporalError::range()))?,
-            time.milliseconds
-                .try_into()
-                .or(Err(TemporalError::range()))?,
-            time.microseconds
-                .try_into()
-                .or(Err(TemporalError::range()))?,
-            time.nanoseconds
-                .try_into()
-                .or(Err(TemporalError::range()))?,
-        )
+            i64::try_from(time.hours).or(Err(TemporalError::range()))?,
+            i64::try_from(time.minutes).or(Err(TemporalError::range()))?,
+            i64::try_from(time.seconds).or(Err(TemporalError::range()))?,
+            i64::try_from(time.milliseconds).or(Err(TemporalError::range()))?,
+            i128::try_from(time.microseconds).or(Err(TemporalError::range()))?,
+            i128::try_from(time.nanoseconds).or(Err(TemporalError::range()))?,
+        )?;
+        if sign == Sign::Negative {
+            duration = duration.negated();
+        }
+        Ok(duration)
     }
 
     /// Returns this `Duration` as a `NormalizedTimeDuration`.
@@ -1519,19 +1518,27 @@ impl FromStr for Duration {
             (0, 0, 0, 0)
         };
 
-        let sign = parse_record.sign as i64;
+        let sign = if parse_record.sign == ixdtf::parsers::records::Sign::Negative {
+            Sign::Negative
+        } else {
+            Sign::Positive
+        };
 
-        Self::new(
-            years as i64 * sign,
-            months as i64 * sign,
-            weeks as i64 * sign,
-            days as i64 * sign,
-            hours as i64 * sign,
-            minutes as i64 * sign,
-            seconds as i64 * sign,
-            millis as i64 * sign,
-            micros as i128 * sign as i128,
-            nanos as i128 * sign as i128,
-        )
+        let mut duration = Self::new(
+            years as i64,
+            months as i64,
+            weeks as i64,
+            days as i64,
+            hours as i64,
+            minutes as i64,
+            seconds as i64,
+            millis as i64,
+            micros as i128,
+            nanos as i128,
+        )?;
+        if sign == Sign::Negative {
+            duration = duration.negated();
+        }
+        Ok(duration)
     }
 }
diff --git a/src/iso.rs b/src/iso.rs
index bf6014d3c..21dbe875b 100644
--- a/src/iso.rs
+++ b/src/iso.rs
@@ -169,12 +169,14 @@ impl IsoDateTime {
         let date = PlainDate::new_unchecked(self.date, calendar);
 
         // 5. Let dateDuration be ? CreateTemporalDuration(years, months, weeks, days + timeResult.[[Days]], 0, 0, 0, 0, 0, 0).
+        let sign = date_duration.sign.as_sign_multiplier();
         let date_duration = DateDuration::new(
-            date_duration.years.into(),
-            date_duration.months.into(),
-            date_duration.weeks.into(),
+            i64::from(date_duration.years) * i64::from(sign),
+            i64::from(date_duration.months) * i64::from(sign),
+            i64::from(date_duration.weeks) * i64::from(sign),
             i64::try_from(date_duration.days)
                 .or(Err(TemporalError::range()))?
+                * i64::from(sign)
                 .checked_add(t_result.0)
                 .ok_or(TemporalError::range())?,
         )?;
@@ -399,9 +401,13 @@ impl IsoDate {
         // 1. Assert: year, month, day, years, months, weeks, and days are integers.
         // 2. Assert: overflow is either "constrain" or "reject".
         // 3. Let intermediate be ! BalanceISOYearMonth(year + years, month + months).
+        let year_offset = i64::from(duration.years)
+            * i64::from(duration.sign.as_sign_multiplier());
+        let month_offset = i64::from(duration.months)
+            * i64::from(duration.sign.as_sign_multiplier());
         let intermediate = balance_iso_year_month_with_clamp(
-            i64::from(self.year) + i64::from(duration.years),
-            i64::from(self.month) + i64::from(duration.months),
+            i64::from(self.year) + year_offset,
+            i64::from(self.month) + month_offset,
         );
 
         // 4. Let intermediate be ? RegulateISODate(intermediate.[[Year]], intermediate.[[Month]], day, overflow).
@@ -410,7 +416,9 @@ impl IsoDate {
 
         // 5. Set days to days + 7 × weeks.
         let additional_days = i64::try_from(duration.days).or(Err(TemporalError::range()))?
-            + (7 * i64::from(duration.weeks)); // Verify
+            * i64::from(duration.sign.as_sign_multiplier())
+            + (7 * i64::from(duration.weeks)
+                * i64::from(duration.sign.as_sign_multiplier()));
 
         // 6. Let d be intermediate.[[Day]] + days.
         let intermediate_days = i64::from(intermediate.day) + additional_days;
diff --git a/src/lib.rs b/src/lib.rs
index 1bc372696..f2f6e21ed 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -259,10 +259,11 @@ impl From<i64> for Sign {
 impl Sign {
     /// Coerces the current `Sign` to be either negative or positive.
     pub(crate) fn as_sign_multiplier(&self) -> i8 {
-        if matches!(self, Self::Zero) {
-            return 1;
+        match self {
+            Self::Positive => 1,
+            Self::Negative => -1,
+            Self::Zero => 0,
         }
-        *self as i8
     }
 
     pub(crate) fn negate(&self) -> Sign {