diff --git a/api/src/main/java/me/lokka30/treasury/api/common/event/EventBus.java b/api/src/main/java/me/lokka30/treasury/api/common/event/EventBus.java
index 63834b6a..b96ae1b5 100644
--- a/api/src/main/java/me/lokka30/treasury/api/common/event/EventBus.java
+++ b/api/src/main/java/me/lokka30/treasury/api/common/event/EventBus.java
@@ -70,7 +70,7 @@ public <T> FireCompletion<T> fire(@NotNull T event) {
         List<Class<?>> friends = eventTypes.getFriendsOf(event.getClass());
         ExecutorService async = EventExecutorTracker.INSTANCE.getExecutor(event.getClass());
         FireCompletion<T> ret = new FireCompletion<>(event.getClass());
-        async.submit(() -> {
+        async.execute(() -> {
             List<Completion> completions = new ArrayList<>();
             EventCaller caller = events.get(event.getClass());
             if (caller != null) {
diff --git a/api/src/main/java/me/lokka30/treasury/api/common/event/EventCaller.java b/api/src/main/java/me/lokka30/treasury/api/common/event/EventCaller.java
index 9ec1f002..9960ce85 100644
--- a/api/src/main/java/me/lokka30/treasury/api/common/event/EventCaller.java
+++ b/api/src/main/java/me/lokka30/treasury/api/common/event/EventCaller.java
@@ -28,7 +28,7 @@ public Completion call(Object event) {
             return Completion.completed();
         }
         Completion completion = new Completion();
-        EventExecutorTracker.INSTANCE.getExecutor(eventClass).submit(() -> {
+        EventExecutorTracker.INSTANCE.getExecutor(eventClass).execute(() -> {
             List<Throwable> errors = call(event, new ArrayList<>(), 0);
             if (!errors.isEmpty()) {
                 completion.completeExceptionally(errors);
diff --git a/api/src/main/java/me/lokka30/treasury/api/common/event/EventTypeTracker.java b/api/src/main/java/me/lokka30/treasury/api/common/event/EventTypeTracker.java
index d02e12e6..c0dc1a87 100644
--- a/api/src/main/java/me/lokka30/treasury/api/common/event/EventTypeTracker.java
+++ b/api/src/main/java/me/lokka30/treasury/api/common/event/EventTypeTracker.java
@@ -6,37 +6,32 @@
 
 import com.google.common.reflect.TypeToken;
 import java.util.Collections;
-import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.stream.Collectors;
+import java.util.stream.Stream;
 
 class EventTypeTracker {
 
-    private Map<Class<?>, List<Class<?>>> friends = new HashMap<>();
+    private final Map<Class<?>, List<Class<?>>> friends = new ConcurrentHashMap<>();
 
-    public List<Class<?>> getFriendsOf(Class<?> eventType) {
-        if (friends.containsKey(eventType)) {
-            return Collections.unmodifiableList(friends.get(eventType));
-        }
-
-        List<Class<?>> types = getEventTypes(eventType);
-        friends.put(
-                eventType,
-                types.stream().filter(type -> type != eventType).collect(Collectors.toList())
-        );
-
-        return friends.get(eventType);
+    public List<Class<?>> getFriendsOf(Class<?> event) {
+        List<Class<?>> computedFriends = friends.computeIfAbsent((event), (eventType) -> {
+            return getEventTypes(eventType)
+                    .filter(type -> type != eventType)
+                    .collect(Collectors.toList());
+        });
+        return Collections.unmodifiableList(computedFriends);
     }
 
-    private static List<Class<?>> getEventTypes(Class<?> eventType) {
+    private static <E> Stream<Class<? super E>> getEventTypes(Class<E> eventType) {
         return TypeToken
                 .of(eventType)
                 .getTypes()
                 .rawTypes()
                 .stream()
-                .filter(type -> type != Object.class && type != Cancellable.class)
-                .collect(Collectors.toList());
+                .filter(type -> type != Object.class && type != Cancellable.class);
     }
 
 }
diff --git a/api/src/main/java/me/lokka30/treasury/api/economy/EconomyProvider.java b/api/src/main/java/me/lokka30/treasury/api/economy/EconomyProvider.java
index 9a47c4f9..c61356cc 100644
--- a/api/src/main/java/me/lokka30/treasury/api/economy/EconomyProvider.java
+++ b/api/src/main/java/me/lokka30/treasury/api/economy/EconomyProvider.java
@@ -4,8 +4,11 @@
 
 package me.lokka30.treasury.api.economy;
 
+import java.util.ArrayList;
 import java.util.Collection;
+import java.util.Collections;
 import java.util.HashSet;
+import java.util.List;
 import java.util.Objects;
 import java.util.Optional;
 import java.util.Set;
@@ -222,20 +225,12 @@ default void retrieveAllAccountsPlayerIsMemberOf(
                 subscription.succeed(identifiers);
                 return;
             }
-            Set<String> ret = new HashSet<>();
+            Set<String> ret = Collections.synchronizedSet(new HashSet<>());
+            List<CompletableFuture<Void>> futures = new ArrayList<>(identifiers.size());
             for (String identifier : identifiers) {
-                EconomySubscriber.<Account>asFuture(subscriber -> retrieveAccount(identifier,
-                        subscriber
-                )).exceptionally(throwable -> {
-                    if (throwable instanceof EconomyException) {
-                        subscription.fail((EconomyException) throwable);
-                    } else {
-                        subscription.fail(new EconomyException(EconomyFailureReason.OTHER_FAILURE,
-                                throwable
-                        ));
-                    }
-                    return null;
-                }).thenCompose(account -> {
+                futures.add(EconomySubscriber.<Account>asFuture(
+                        subscriber -> retrieveAccount(identifier, subscriber)
+                ).thenCompose(account -> {
                     if (account == null) {
                         return CompletableFuture.completedFuture(false);
                     }
@@ -250,10 +245,22 @@ default void retrieveAllAccountsPlayerIsMemberOf(
                     if (val) {
                         ret.add(identifier);
                     }
-                });
-
+                }));
             }
-            subscription.succeed(ret);
+            CompletableFuture.allOf(futures.toArray(new CompletableFuture[0]))
+                    .thenRun(() -> {
+                        subscription.succeed(ret);
+                    })
+                    .exceptionally((throwable) -> {
+                        if (throwable instanceof EconomyException) {
+                            subscription.fail((EconomyException) throwable);
+                        } else {
+                            subscription.fail(new EconomyException(EconomyFailureReason.OTHER_FAILURE,
+                                    throwable
+                            ));
+                        }
+                        return null;
+                    });
         });
     }
 
@@ -288,20 +295,12 @@ default void retrieveAllAccountsPlayerHasPermission(
                 subscription.succeed(identifiers);
                 return;
             }
-            Set<String> ret = new HashSet<>();
+            Set<String> ret = Collections.synchronizedSet(new HashSet<>());
+            List<CompletableFuture<Void>> futures = new ArrayList<>(identifiers.size());
             for (String identifier : identifiers) {
-                EconomySubscriber.<Account>asFuture(subscriber -> retrieveAccount(identifier,
-                        subscriber
-                )).exceptionally(throwable -> {
-                    if (throwable instanceof EconomyException) {
-                        subscription.fail((EconomyException) throwable);
-                    } else {
-                        subscription.fail(new EconomyException(EconomyFailureReason.OTHER_FAILURE,
-                                throwable
-                        ));
-                    }
-                    return null;
-                }).thenCompose(account -> {
+                futures.add(EconomySubscriber.<Account>asFuture(
+                        subscriber -> retrieveAccount(identifier, subscriber)
+                ).thenCompose(account -> {
                     if (account == null) {
                         return CompletableFuture.completedFuture(false);
                     }
@@ -327,9 +326,22 @@ public void fail(@NotNull final EconomyException exception) {
                     if (val) {
                         ret.add(identifier);
                     }
-                });
+                }));
             }
-            subscription.succeed(ret);
+            CompletableFuture.allOf(futures.toArray(new CompletableFuture[0]))
+                    .thenRun(() -> {
+                        subscription.succeed(ret);
+                    })
+                    .exceptionally((throwable) -> {
+                        if (throwable instanceof EconomyException) {
+                            subscription.fail((EconomyException) throwable);
+                        } else {
+                            subscription.fail(new EconomyException(EconomyFailureReason.OTHER_FAILURE,
+                                    throwable
+                            ));
+                        }
+                        return null;
+                    });
         });
     }