diff --git a/hledger-lib/Hledger/Data/Dates.hs b/hledger-lib/Hledger/Data/Dates.hs
index 00f3fdf81..8230ec39e 100644
--- a/hledger-lib/Hledger/Data/Dates.hs
+++ b/hledger-lib/Hledger/Data/Dates.hs
@@ -75,7 +75,7 @@ module Hledger.Data.Dates (
   daysInSpan,
 
   tests_Dates
-, intervalStartBefore)
+, intervalBoundaryBefore)
 where
 
 import qualified Control.Monad.Fail as Fail (MonadFail, fail)
@@ -548,8 +548,8 @@ nextyear = startofyear . addGregorianYearsClip 1
 startofyear day = fromGregorian y 1 1 where (y,_,_) = toGregorian day
 
 -- Get the natural start for the given interval that falls on or before the given day.
-intervalStartBefore :: Interval -> Day -> Day
-intervalStartBefore int d =
+intervalBoundaryBefore :: Interval -> Day -> Day
+intervalBoundaryBefore int d =
   case splitSpan int (DateSpan (Just d) (Just $ addDays 1 d)) of
     (DateSpan (Just start) _:_) -> start
     _ -> d
diff --git a/hledger-lib/Hledger/Reports/BudgetReport.hs b/hledger-lib/Hledger/Reports/BudgetReport.hs
index cca06096a..952fb875e 100644
--- a/hledger-lib/Hledger/Reports/BudgetReport.hs
+++ b/hledger-lib/Hledger/Reports/BudgetReport.hs
@@ -139,7 +139,7 @@ journalAddBudgetGoalTransactions bopts ropts reportspan j =
                     pts -> (ptinterval pt, ptspan pt)
                       where pt = maximumBy (comparing ptinterval) pts  -- PARTIAL: maximumBy won't fail
                 -- the natural start of this interval on or before the journal/report start
-                intervalstart = intervalStartBefore intervl d
+                intervalstart = intervalBoundaryBefore intervl d
                 -- the natural interval start before the journal/report start,
                 -- or the rule-specified start if later,
                 -- but no later than the journal/report start.