diff --git a/tracker/rerank_helpers.py b/tracker/rerank_helpers.py
new file mode 100644
index 0000000..f27582c
--- /dev/null
+++ b/tracker/rerank_helpers.py
@@ -0,0 +1,133 @@
+# Copyright 2016 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file or at
+# https://developers.google.com/open-source/licenses/bsd
+
+"""Functions to help rerank issues in a lit.
+
+This file contains methods that implement a reranking algorithm for
+issues in a list.
+"""
+
+from __future__ import division
+from __future__ import print_function
+from __future__ import absolute_import
+
+import sys
+
+from framework import exceptions
+
+MAX_RANKING = sys.maxint
+MIN_RANKING = 0
+
+def GetHotlistRerankChanges(hotlist_items, moved_issue_ids, target_position):
+  # type: (int, Sequence[int], int) -> Collection[Tuple[int, int]]
+  """Computes the new ranks from reranking and or inserting of HotlistItems.
+
+  Args:
+    hotlist_items: The current list of HotlistItems in the Hotlist.
+    moved_issue_ids: A list of issue IDs to be moved/inserted together,
+      in the order
+      they should have the reranking.
+    target_position: The index, starting at 0, of the new position the
+      first issue in moved_issue_ids should occupy in the updated ordering.
+      Therefore this value cannot be greater than
+      (len(hotlist.items) - len(moved_issue_ids)).
+
+  Returns:
+    A list of [(issue_id, rank), ...] of HotlistItems that need to be updated.
+
+  Raises:
+    InputException: If the target_position is not valid.
+  """
+  # Sort hotlist items by rank.
+  sorted_hotlist_items = sorted(hotlist_items, key=lambda item: item.rank)
+  unmoved_hotlist_items = [
+      item for item in sorted_hotlist_items
+      if item.issue_id not in moved_issue_ids]
+  if target_position < 0:
+    raise exceptions.InputException(
+        'given `target_position`: %d, must be non-negative')
+  if target_position > len(unmoved_hotlist_items):
+    raise exceptions.InputException(
+        '`target_position` %d is higher than maximum allowed (%d) for'
+        'moving %d items in a hotlist with %d items total.' % (
+            target_position, len(unmoved_hotlist_items),
+            len(moved_issue_ids), len(sorted_hotlist_items)))
+  lower, higher = [], []
+  for i, item in enumerate(unmoved_hotlist_items):
+    item_tuple = (item.issue_id, item.rank)
+    if i < target_position:
+      lower.append(item_tuple)
+    else:
+      higher.append(item_tuple)
+
+  return GetInsertRankings(lower, higher, moved_issue_ids)
+
+def GetInsertRankings(lower, higher, moved_ids):
+  """Compute rankings for moved_ids to insert between the
+  lower and higher rankings
+
+  Args:
+    lower: a list of [(id, rank),...] of blockers that should have
+      a lower rank than the moved issues. Should be sorted from highest
+      to lowest rank.
+    higher: a list of [(id, rank),...] of blockers that should have
+      a higher rank than the moved issues. Should be sorted from highest
+      to lowest rank.
+    moved_ids: a list of global IDs for issues to re-rank.
+
+  Returns:
+    a list of [(id, rank),...] of blockers that need to be updated. rank
+    is the new rank of the issue with the specified id.
+  """
+  if lower:
+    lower_rank = lower[-1][1]
+  else:
+    lower_rank = MIN_RANKING
+
+  if higher:
+    higher_rank = higher[0][1]
+  else:
+    higher_rank = MAX_RANKING
+
+  slot_count = higher_rank - lower_rank - 1
+  if slot_count >= len(moved_ids):
+    new_ranks = _DistributeRanks(lower_rank, higher_rank, len(moved_ids))
+    return list(zip(moved_ids, new_ranks))
+  else:
+    new_lower, new_higher, new_moved_ids = _ResplitRanks(
+        lower, higher, moved_ids)
+    if not new_moved_ids:
+      return None
+    else:
+      return GetInsertRankings(new_lower, new_higher, new_moved_ids)
+
+
+def _DistributeRanks(low, high, rank_count):
+  """Compute evenly distributed ranks in a range"""
+  bucket_size = (high - low) // rank_count
+  first_rank = low + (bucket_size + 1) // 2
+  return list(range(first_rank, high, bucket_size))
+
+
+def _ResplitRanks(lower, higher, moved_ids):
+  if not (lower or higher):
+    return None, None, None
+
+  if not lower:
+    take_from = 'higher'
+  elif not higher:
+    take_from = 'lower'
+  else:
+    next_lower = lower[-2][1] if len(lower) >= 2 else MIN_RANKING
+    next_higher = higher[1][1] if len(higher) >= 2 else MAX_RANKING
+    if (lower[-1][1] - next_lower) > (next_higher - higher[0][1]):
+      take_from = 'lower'
+    else:
+      take_from = 'higher'
+
+  if take_from == 'lower':
+    return (lower[:-1], higher, [lower[-1][0]] + moved_ids)
+  else:
+    return (lower, higher[1:], moved_ids + [higher[0][0]])