diff --git a/handler/transaction.go b/handler/transaction.go
index 9768c90..f6d79c6 100644
--- a/handler/transaction.go
+++ b/handler/transaction.go
@@ -228,7 +228,7 @@ func (h TransactionImpl) getTransactionData(accounts []*types.Account, treasureC
 	treasureChestMap := make(map[uuid.UUID]string, 0)
 	root := ""
 	for _, treasureChest := range treasureChests {
-		if treasureChest.ParentId == uuid.Nil {
+		if treasureChest.ParentId == nil {
 			root = treasureChest.Name + " > "
 			treasureChestMap[treasureChest.Id] = treasureChest.Name
 		} else {
diff --git a/migration/007_treasure_chest_parent_id_fix.up.sql b/migration/007_treasure_chest_parent_id_fix.up.sql
new file mode 100644
index 0000000..c99bab3
--- /dev/null
+++ b/migration/007_treasure_chest_parent_id_fix.up.sql
@@ -0,0 +1,3 @@
+UPDATE treasure_chest
+SET parent_id = NULL
+WHERE parent_id = "00000000-0000-0000-0000-000000000000";
diff --git a/service/default.go b/service/default.go
index cd71904..130f672 100644
--- a/service/default.go
+++ b/service/default.go
@@ -6,7 +6,7 @@ import (
 )
 
 var (
-	safeInputRegex = regexp.MustCompile(`^[a-zA-Z0-9ÄÖÜäöüß, -]+$`)
+	safeInputRegex = regexp.MustCompile(`^[a-zA-Z0-9ÄÖÜäöüß,& -]+$`)
 )
 
 func validateString(value string, fieldName string) error {
diff --git a/service/transaction.go b/service/transaction.go
index 6e49440..6cab62b 100644
--- a/service/transaction.go
+++ b/service/transaction.go
@@ -424,6 +424,7 @@ func (s TransactionImpl) RecalculateBalances(user *types.User) error {
 			if err != nil {
 				return err
 			}
+
 		}
 	}
 
@@ -493,14 +494,17 @@ func (s TransactionImpl) validateAndEnrichTransaction(tx *sqlx.Tx, oldTransactio
 			return nil, fmt.Errorf("could not parse treasureChestId: %w", ErrBadRequest)
 		}
 		treasureChestUuid = &temp
-		err = tx.Get(&rowCount, `SELECT COUNT(*) FROM treasure_chest WHERE id = ? AND user_id = ?`, treasureChestUuid, userId)
+		var treasureChest types.TreasureChest
+		err = tx.Get(&treasureChest, `SELECT * FROM treasure_chest WHERE id = ? AND user_id = ?`, treasureChestUuid, userId)
 		err = db.TransformAndLogDbError("transaction validate", nil, err)
 		if err != nil {
+			if err == db.ErrNotFound {
+				return nil, fmt.Errorf("treasure chest not found: %w", ErrBadRequest)
+			}
 			return nil, err
 		}
-		if rowCount == 0 {
-			log.Error("transaction validate: %v", err)
-			return nil, fmt.Errorf("treasure chest not found: %w", ErrBadRequest)
+		if treasureChest.ParentId == nil {
+			return nil, fmt.Errorf("treasure chest is a group: %w", ErrBadRequest)
 		}
 	}
 
diff --git a/service/treasure_chest.go b/service/treasure_chest.go
index 834d778..ab865f7 100644
--- a/service/treasure_chest.go
+++ b/service/treasure_chest.go
@@ -65,16 +65,16 @@ func (s TreasureChestImpl) Add(user *types.User, parentId, name string) (*types.
 		return nil, err
 	}
 
-	parentUuid := uuid.Nil
+	var parentUuid *uuid.UUID
 	if parentId != "" {
 		parent, err := s.Get(user, parentId)
 		if err != nil {
 			return nil, err
 		}
-		if parent.ParentId != uuid.Nil {
+		if parent.ParentId != nil {
 			return nil, fmt.Errorf("only a depth of 1 allowed: %w", ErrBadRequest)
 		}
-		parentUuid = parent.Id
+		parentUuid = &parent.Id
 	}
 
 	treasureChest := &types.TreasureChest{
@@ -137,7 +137,7 @@ func (s TreasureChestImpl) Update(user *types.User, idStr, parentId, name string
 		return nil, types.ErrInternal
 	}
 
-	parentUuid := uuid.Nil
+	var parentUuid *uuid.UUID
 	if parentId != "" {
 		parent, err := s.Get(user, parentId)
 		if err != nil {
@@ -149,11 +149,11 @@ func (s TreasureChestImpl) Update(user *types.User, idStr, parentId, name string
 		if err != nil {
 			return nil, err
 		}
-		if parent.ParentId != uuid.Nil || childCount > 0 {
+		if parent.ParentId != nil || childCount > 0 {
 			return nil, fmt.Errorf("only one level allowed: %w", ErrBadRequest)
 		}
 
-		parentUuid = parent.Id
+		parentUuid = &parent.Id
 	}
 
 	timestamp := s.clock.Now()
@@ -292,10 +292,10 @@ func sortTree(nodes []*types.TreasureChest) []*types.TreasureChest {
 	children := make(map[uuid.UUID][]*types.TreasureChest)
 
 	for _, node := range nodes {
-		if node.ParentId == uuid.Nil {
+		if node.ParentId == nil {
 			roots = append(roots, node)
 		} else {
-			children[node.ParentId] = append(children[node.ParentId], node)
+			children[*node.ParentId] = append(children[*node.ParentId], node)
 		}
 	}
 
diff --git a/template/transaction/transaction.templ b/template/transaction/transaction.templ
index d141443..94370ca 100644
--- a/template/transaction/transaction.templ
+++ b/template/transaction/transaction.templ
@@ -27,10 +27,10 @@ templ Transaction(items templ.Component, filter types.TransactionItemsFilter, ac
 				<select name="treasure-chest-id" class="bg-white input">
 					<option value="">- Filter Treasure Chest -</option>
 					for _, parent := range treasureChests {
-						if parent.ParentId == uuid.Nil {
+						if parent.ParentId == nil {
 							<optgroup label={ parent.Name }>
 								for _, child := range treasureChests {
-									if child.ParentId == parent.Id {
+									if *child.ParentId == parent.Id {
 										<option
 											value={ child.Id.String() }
 											selected?={ filter.TreasureChestId == child.Id.String() }
@@ -158,19 +158,21 @@ templ EditTransaction(transaction *types.Transaction, accounts []*types.Account,
 					}
 				</select>
 				<label for="treasure-chest-id" class="text-sm text-gray-500">Treasure Chest</label>
-				<select
-					name="treasure-chest-id"
-					class="bg-white input"
-				>
-					<option value="">-</option>
-					for _, treasureChest := range treasureChests {
-						<option selected?={ treasureChest.Id.String() == treasureChestId } value={ treasureChest.Id.String() }>
-							if treasureChest.ParentId != uuid.Nil {
-								&nbsp;&nbsp;&nbsp;{ treasureChest.Name }
-							} else {
-								{ treasureChest.Name }
-							}
-						</option>
+				<select name="treasure-chest-id" class="bg-white input">
+					<option value="">- Filter Treasure Chest -</option>
+					for _, parent := range treasureChests {
+						if parent.ParentId == nil {
+							<optgroup label={ parent.Name }>
+								for _, child := range treasureChests {
+									if *child.ParentId == parent.Id {
+										<option
+											value={ child.Id.String() }
+											selected?={ treasureChestId == child.Id.String() }
+										>{ child.Name }</option>
+									}
+								}
+							</optgroup>
+						}
 					}
 				</select>
 			</div>
diff --git a/template/treasurechest/treasure_chest.templ b/template/treasurechest/treasure_chest.templ
index d6024bb..76441c7 100644
--- a/template/treasurechest/treasure_chest.templ
+++ b/template/treasurechest/treasure_chest.templ
@@ -41,7 +41,9 @@ templ EditTreasureChest(treasureChest *types.TreasureChest, parents []*types.Tre
 	} else {
 		id = treasureChest.Id.String()
 		name = treasureChest.Name
-		parentId = treasureChest.ParentId
+		if treasureChest.ParentId != nil {
+			parentId = *treasureChest.ParentId
+		}
 		cancelUrl = "/treasurechest/" + id
 	}
 	}}
@@ -93,23 +95,27 @@ templ EditTreasureChest(treasureChest *types.TreasureChest, parents []*types.Tre
 templ TreasureChestItem(treasureChest *types.TreasureChest) {
 	{{
 	var identation string
-	if treasureChest.ParentId != uuid.Nil {
+	viewTransactions := ""
+	if treasureChest.ParentId != nil {
 		identation = " mt-2 ml-36"
 	} else {
 		identation = " mt-8"
+		viewTransactions = "hidden"
 	}
 	}}
 	<div id="treasurechest" class={ "border-1 border-gray-300 w-full p-4 bg-gray-50 rounded-lg" + identation }>
 		<div class="text-xl flex justify-end items-center gap-4">
 			<p class="mr-auto">{ treasureChest.Name }</p>
-			if treasureChest.CurrentBalance < 0 {
-				<p class="mr-20 text-red-700">{ displayBalance(treasureChest.CurrentBalance) }</p>
-			} else {
-				<p class="mr-20 text-green-700">{ displayBalance(treasureChest.CurrentBalance) }</p>
+			if treasureChest.ParentId != nil {
+				if treasureChest.CurrentBalance < 0 {
+					<p class="mr-20 text-red-700">{ displayBalance(treasureChest.CurrentBalance) }</p>
+				} else {
+					<p class="mr-20 text-green-700">{ displayBalance(treasureChest.CurrentBalance) }</p>
+				}
 			}
 			<a
 				href={ templ.URL("/transaction?treasure-chest-id=" + treasureChest.Id.String()) }
-				class="button button-neglect px-1 flex items-center gap-2"
+				class={ "button button-neglect px-1 flex items-center gap-2 " + viewTransactions }
 				title="View transactions"
 			>
 				@svg.Eye()
@@ -147,7 +153,7 @@ func filterNoChildNoSelf(nodes []*types.TreasureChest, selfId string) []*types.T
 	var result []*types.TreasureChest
 
 	for _, node := range nodes {
-		if node.ParentId == uuid.Nil && node.Id.String() != selfId {
+		if node.ParentId == nil && node.Id.String() != selfId {
 			result = append(result, node)
 		}
 	}
diff --git a/types/treasure_chest.go b/types/treasure_chest.go
index 6bf5cb8..cd5369e 100644
--- a/types/treasure_chest.go
+++ b/types/treasure_chest.go
@@ -13,8 +13,8 @@ import (
 // Imagne a TreasureChest for free time activities, where some money is spend in cash and some other with credit card
 type TreasureChest struct {
 	Id       uuid.UUID
-	ParentId uuid.UUID `db:"parent_id"`
-	UserId   uuid.UUID `db:"user_id"`
+	ParentId *uuid.UUID `db:"parent_id"`
+	UserId   uuid.UUID  `db:"user_id"`
 
 	Name string