diff --git a/contracts/incentives/src/contract.rs b/contracts/incentives/src/contract.rs
index a877040f5..37b97456a 100644
--- a/contracts/incentives/src/contract.rs
+++ b/contracts/incentives/src/contract.rs
@@ -1,10 +1,8 @@
-use std::collections::HashMap;
-
 #[cfg(not(feature = "library"))]
 use cosmwasm_std::entry_point;
 use cosmwasm_std::{
-    attr, coins, to_binary, Addr, BankMsg, Binary, Coin, CosmosMsg, Decimal, Deps, DepsMut, Env,
-    Event, MessageInfo, Order, Response, StdError, StdResult, Uint128,
+    attr, to_binary, Addr, BankMsg, Binary, Coin, Coins, Decimal, Deps, DepsMut, Env, Event,
+    MessageInfo, Order, Response, StdError, StdResult, Uint128,
 };
 use cw_storage_plus::Bound;
 use mars_owner::{OwnerInit::SetInitialOwner, OwnerUpdate};
@@ -447,7 +445,7 @@ pub fn execute_claim_rewards(
     } else {
         base_event
     };
-    let mut events = vec![base_event];
+    response = response.add_event(base_event);
 
     let asset_incentives = state::paginate_incentive_states(
         deps.storage,
@@ -456,7 +454,7 @@ pub fn execute_claim_rewards(
         limit,
     )?;
 
-    let mut total_unclaimed_rewards: HashMap<String, Uint128> = HashMap::new();
+    let mut total_unclaimed_rewards = Coins::default();
 
     for ((collateral_denom, incentive_denom), _) in asset_incentives {
         let querier = deps.querier;
@@ -478,25 +476,25 @@ pub fn execute_claim_rewards(
             &Uint128::zero(),
         )?;
 
-        total_unclaimed_rewards
-            .entry(incentive_denom)
-            .and_modify(|amount| *amount += unclaimed_rewards)
-            .or_insert(unclaimed_rewards);
+        total_unclaimed_rewards.add(Coin {
+            denom: incentive_denom,
+            amount: unclaimed_rewards,
+        })?;
     }
 
-    for (denom, amount) in total_unclaimed_rewards.iter() {
-        response = response.add_message(CosmosMsg::Bank(BankMsg::Send {
-            to_address: user_addr.to_string(),
-            amount: coins(amount.u128(), denom),
-        }));
-        events.push(
-            Event::new("mars/incentives/claim_rewards/claimed_reward")
-                .add_attribute("denom", denom)
-                .add_attribute("amount", *amount),
-        );
+    if !total_unclaimed_rewards.is_empty() {
+        response = response
+            .add_event(
+                Event::new("mars/incentives/claim_rewards/claimed_rewards")
+                    .add_attribute("coins", total_unclaimed_rewards.to_string()),
+            )
+            .add_message(BankMsg::Send {
+                to_address: user_addr.into(),
+                amount: total_unclaimed_rewards.into(),
+            });
     }
 
-    Ok(response.add_events(events))
+    Ok(response)
 }
 
 pub fn execute_update_config(
@@ -675,7 +673,7 @@ pub fn query_user_unclaimed_rewards(
         limit,
     )?;
 
-    let mut total_unclaimed_rewards: HashMap<String, Uint128> = HashMap::new();
+    let mut total_unclaimed_rewards = Coins::default();
 
     for ((collateral_denom, incentive_denom), _) in incentive_states {
         let unclaimed_rewards = compute_user_unclaimed_rewards(
@@ -688,19 +686,14 @@ pub fn query_user_unclaimed_rewards(
             &collateral_denom,
             &incentive_denom,
         )?;
-        total_unclaimed_rewards
-            .entry(incentive_denom)
-            .and_modify(|amount| *amount += unclaimed_rewards)
-            .or_insert(unclaimed_rewards);
+
+        total_unclaimed_rewards.add(Coin {
+            denom: incentive_denom,
+            amount: unclaimed_rewards,
+        })?;
     }
 
-    Ok(total_unclaimed_rewards
-        .into_iter()
-        .map(|(denom, amount)| Coin {
-            denom,
-            amount,
-        })
-        .collect())
+    Ok(total_unclaimed_rewards.into())
 }
 
 fn query_red_bank_address(deps: Deps) -> StdResult<Addr> {
diff --git a/contracts/incentives/tests/test_claim_rewards.rs b/contracts/incentives/tests/test_claim_rewards.rs
index 8320d81ec..af545c28d 100644
--- a/contracts/incentives/tests/test_claim_rewards.rs
+++ b/contracts/incentives/tests/test_claim_rewards.rs
@@ -226,6 +226,10 @@ fn execute_claim_rewards() {
     let res = execute(deps.as_mut(), env.clone(), info, msg).unwrap();
 
     // query after execution gives 0 rewards
+    //
+    // NOTE: the query should return an empty array, instead of a non-empty array
+    // with a zero-amount coin! the latter is considered an invalid coins array
+    // and will result in error.
     let rewards_query_after = query_user_unclaimed_rewards(
         deps.as_ref(),
         env,
@@ -236,7 +240,7 @@ fn execute_claim_rewards() {
         None,
     )
     .unwrap();
-    assert_eq!(rewards_query_after[0].amount, Uint128::zero());
+    assert!(rewards_query_after.is_empty());
 
     // ASSERT
 
@@ -254,7 +258,7 @@ fn execute_claim_rewards() {
     );
     assert_eq!(
         res.events[1].attributes,
-        vec![attr("denom", "umars"), attr("amount", expected_accrued_rewards),]
+        vec![attr("coins", format!("{expected_accrued_rewards}umars"))]
     );
     // asset and zero incentives get updated, no_user does not
     let asset_incentive =