diff --git a/x/distribution/keeper/delegation.go b/x/distribution/keeper/delegation.go
index 8183d95b1a54..4132976ef640 100644
--- a/x/distribution/keeper/delegation.go
+++ b/x/distribution/keeper/delegation.go
@@ -77,6 +77,7 @@ func (k Keeper) WithdrawDelegationReward(ctx sdk.Context, delegatorAddr sdk.AccA
 		return types.ErrNoDelegationDistInfo(k.codespace)
 	}
 
+	// TODO: Reconcile with duplicate code in getDelegatorRewardsAll.
 	height := ctx.BlockHeight()
 	bondedTokens := k.stakeKeeper.TotalPower(ctx)
 	feePool := k.GetFeePool(ctx)
@@ -125,6 +126,7 @@ func (k Keeper) getDelegatorRewardsAll(ctx sdk.Context, delAddr sdk.AccAddress,
 	bondedTokens := k.stakeKeeper.TotalPower(ctx)
 
 	// iterate over all the delegations
+	// TODO: Reconcile with duplicate code in WithdrawDelegationReward.
 	operationAtDelegation := func(_ int64, del sdk.Delegation) (stop bool) {
 		feePool := k.GetFeePool(ctx)
 		valAddr := del.GetValidator()
diff --git a/x/stake/keeper/key.go b/x/stake/keeper/key.go
index d5f2fc9d9e33..91ea7d709cde 100644
--- a/x/stake/keeper/key.go
+++ b/x/stake/keeper/key.go
@@ -61,7 +61,7 @@ func GetValidatorsByPowerIndexKey(validator types.Validator, pool types.Pool) []
 }
 
 // get the bonded validator index key for an operator address
-func GetBondedValidatorIndexKey(operator sdk.ValAddress) []byte {
+func GetValidatorsBondedIndexKey(operator sdk.ValAddress) []byte {
 	return append(ValidatorsBondedIndexKey, operator...)
 }
 
diff --git a/x/stake/keeper/val_state_change.go b/x/stake/keeper/val_state_change.go
index e123bb2b0a8e..2c832a8ad2b7 100644
--- a/x/stake/keeper/val_state_change.go
+++ b/x/stake/keeper/val_state_change.go
@@ -11,7 +11,11 @@ import (
 	"github.com/cosmos/cosmos-sdk/x/stake/types"
 )
 
-// Apply and return accumulated updates to the bonded validator set
+// Apply and return accumulated updates to the bonded validator set. Also,
+// * Updates the active bonded valset as keyed by GetValidatorsBondedIndexKey().
+// * Updates validator status' according to updated powers.
+// * Updates the fee pool bonded vs loose tokens.
+// * Updates relevant indices.
 //
 // CONTRACT: Only validators with non-zero power or zero-power that were bonded
 // at the previous block height or were removed from the validator set entirely
@@ -21,7 +25,9 @@ func (k Keeper) ApplyAndReturnValidatorSetUpdates(ctx sdk.Context) (updates []ab
 	store := ctx.KVStore(k.storeKey)
 	maxValidators := k.GetParams(ctx).MaxValidators
 
-	// retrieve last validator set
+	// Retrieve the last validator set.
+	// This persistent set is updated later in this function.
+	// (see GetValidatorsBondedIndexKey()).
 	last := k.retrieveLastValidatorSet(ctx)
 
 	// iterate over validators, highest power to lowest
@@ -73,7 +79,7 @@ func (k Keeper) ApplyAndReturnValidatorSetUpdates(ctx sdk.Context) (updates []ab
 		delete(last, operatorBytes)
 
 		// set the bonded validator index
-		store.Set(GetBondedValidatorIndexKey(operator), newPowerBytes)
+		store.Set(GetValidatorsBondedIndexKey(operator), newPowerBytes)
 
 		// keep count
 		count++
@@ -98,7 +104,7 @@ func (k Keeper) ApplyAndReturnValidatorSetUpdates(ctx sdk.Context) (updates []ab
 		}
 
 		// delete from the bonded validator index
-		store.Delete(GetBondedValidatorIndexKey(operator))
+		store.Delete(GetValidatorsBondedIndexKey(operator))
 
 		// update the validator set
 		updates = append(updates, validator.ABCIValidatorUpdateZero())