diff --git a/database/crud/currency.py b/database/crud/currency.py
index 3ef4de0..612b969 100644
--- a/database/crud/currency.py
+++ b/database/crud/currency.py
@@ -1,4 +1,5 @@
 from datetime import datetime
+from typing import Union
 
 from sqlalchemy.ext.asyncio import AsyncSession
 
@@ -17,6 +18,23 @@ async def get_bank(session: AsyncSession, user_id: int) -> Bank:
     return user.bank
 
 
+async def invest(session: AsyncSession, user_id: int, amount: Union[str, int]) -> int:
+    """Invest all your Dinks"""
+    bank = await get_bank(session, user_id)
+    if amount == "all":
+        amount = bank.dinks
+
+    amount = int(amount)
+
+    bank.dinks -= amount
+    bank.invested += amount
+
+    session.add(bank)
+    await session.commit()
+
+    return amount
+
+
 async def add_dinks(session: AsyncSession, user_id: int, amount: int):
     """Increase the Dinks counter for a user"""
     bank = await get_bank(session, user_id)
@@ -44,9 +62,9 @@ async def claim_nightly(session: AsyncSession, user_id: int):
     await session.commit()
 
 
-async def upgrade_capacity(database_session: AsyncSession, user_id: int) -> int:
+async def upgrade_capacity(session: AsyncSession, user_id: int) -> int:
     """Upgrade capacity level"""
-    bank = await get_bank(database_session, user_id)
+    bank = await get_bank(session, user_id)
     upgrade_price = capacity_upgrade_price(bank.capacity_level)
 
     # Can't afford this upgrade
@@ -56,15 +74,15 @@ async def upgrade_capacity(database_session: AsyncSession, user_id: int) -> int:
     bank.dinks -= upgrade_price
     bank.capacity_level += 1
 
-    database_session.add(bank)
-    await database_session.commit()
+    session.add(bank)
+    await session.commit()
 
     return bank.capacity_level
 
 
-async def upgrade_interest(database_session: AsyncSession, user_id: int) -> int:
+async def upgrade_interest(session: AsyncSession, user_id: int) -> int:
     """Upgrade interest level"""
-    bank = await get_bank(database_session, user_id)
+    bank = await get_bank(session, user_id)
     upgrade_price = interest_upgrade_price(bank.interest_level)
 
     # Can't afford this upgrade
@@ -74,15 +92,15 @@ async def upgrade_interest(database_session: AsyncSession, user_id: int) -> int:
     bank.dinks -= upgrade_price
     bank.interest_level += 1
 
-    database_session.add(bank)
-    await database_session.commit()
+    session.add(bank)
+    await session.commit()
 
     return bank.interest_level
 
 
-async def upgrade_rob(database_session: AsyncSession, user_id: int) -> int:
+async def upgrade_rob(session: AsyncSession, user_id: int) -> int:
     """Upgrade rob level"""
-    bank = await get_bank(database_session, user_id)
+    bank = await get_bank(session, user_id)
     upgrade_price = rob_upgrade_price(bank.rob_level)
 
     # Can't afford this upgrade
@@ -92,7 +110,7 @@ async def upgrade_rob(database_session: AsyncSession, user_id: int) -> int:
     bank.dinks -= upgrade_price
     bank.rob_level += 1
 
-    database_session.add(bank)
-    await database_session.commit()
+    session.add(bank)
+    await session.commit()
 
     return bank.rob_level
diff --git a/didier/cogs/currency.py b/didier/cogs/currency.py
index d4910ee..bb46bb0 100644
--- a/didier/cogs/currency.py
+++ b/didier/cogs/currency.py
@@ -113,9 +113,25 @@ class Currency(commands.Cog):
             plural = pluralize("Didier Dink", bank.dinks)
             await ctx.reply(f"**{ctx.author.display_name}** heeft **{bank.dinks}** {plural}.", mention_author=False)
 
+    @commands.command(name="Invest")
+    async def invest(self, ctx: commands.Context, amount: abbreviated_number):  # type: ignore
+        """Invest a given amount of Didier Dinks"""
+        amount = typing.cast(typing.Union[str, int], amount)
+
+        async with self.client.db_session as session:
+            invested = await crud.invest(session, ctx.author.id, amount)
+            plural = pluralize("Didier Dink", invested)
+
+            if invested == 0:
+                await ctx.reply("Je hebt geen Didier Dinks om te investeren.", mention_author=False)
+            else:
+                await ctx.reply(
+                    f"**{ctx.author.display_name}** heeft **{invested}** {plural} geïnvesteerd.", mention_author=False
+                )
+
     @commands.hybrid_command(name="nightly")
     async def nightly(self, ctx: commands.Context):
-        """Claim nightly Dinks"""
+        """Claim nightly Didier Dinks"""
         async with self.client.db_session as session:
             try:
                 await crud.claim_nightly(session, ctx.author.id)
diff --git a/didier/utils/discord/converters/numbers.py b/didier/utils/discord/converters/numbers.py
index 8019fa5..f184ca8 100644
--- a/didier/utils/discord/converters/numbers.py
+++ b/didier/utils/discord/converters/numbers.py
@@ -1,16 +1,18 @@
 import math
-from typing import Optional
-
+from typing import Optional, Union
 
 __all__ = ["abbreviated_number"]
 
 
-def abbreviated_number(argument: str) -> int:
+def abbreviated_number(argument: str) -> Union[str, int]:
     """Custom converter to allow numbers to be abbreviated
     Examples:
         515k
         4m
     """
+    if argument.lower() == "all":
+        return "all"
+
     if not argument:
         raise ValueError