diff --git a/db/schema/schema.sql b/db/schema/schema.sql
index df62bba..41a6752 100644
--- a/db/schema/schema.sql
+++ b/db/schema/schema.sql
@@ -1,12 +1,13 @@
 CREATE TABLE IF NOT EXISTS instruments (
     id INTEGER PRIMARY KEY AUTOINCREMENT,
-    symbol TEXT NOT NULL UNIQUE,
+    symbol TEXT NOT NULL,
     asset_type TEXT NOT NULL,
     exchange TEXT,
     quote_currency TEXT NOT NULL,
     created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
     updated_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
-    deleted_at TIMESTAMP
+    deleted_at TIMESTAMP,
+    UNIQUE(symbol, exchange)
 );
 
 CREATE TABLE IF NOT EXISTS portfolios (
diff --git a/internal/db/migrations/20260411114506_internal_db_migrations_sqlite.initial_setup.sql b/internal/db/migrations/20260411114506_internal_db_migrations_sqlite.initial_setup.sql
index 362882e..269b512 100644
--- a/internal/db/migrations/20260411114506_internal_db_migrations_sqlite.initial_setup.sql
+++ b/internal/db/migrations/20260411114506_internal_db_migrations_sqlite.initial_setup.sql
@@ -2,13 +2,14 @@
 -- +goose StatementBegin
 CREATE TABLE IF NOT EXISTS instruments (
     id INTEGER PRIMARY KEY AUTOINCREMENT,
-    symbol TEXT NOT NULL UNIQUE,
+    symbol TEXT NOT NULL,
     asset_type TEXT NOT NULL,
     exchange TEXT,
     quote_currency TEXT NOT NULL,
     created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
     updated_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
-    deleted_at TIMESTAMP
+    deleted_at TIMESTAMP,
+    UNIQUE(symbol, exchange)
 );
 
 CREATE TABLE IF NOT EXISTS portfolios (
diff --git a/internal/repository/instrument_repo.go b/internal/repository/instrument_repo.go
index f96f2d1..bc388aa 100644
--- a/internal/repository/instrument_repo.go
+++ b/internal/repository/instrument_repo.go
@@ -73,7 +73,7 @@ func (r *InstrumentRepository) Create(ctx context.Context, in Instrument) (Instr
 				"instrument %q on exchange %q: %w",
 				in.Symbol,
 				in.Exchange,
-				domain.ErrPositionAlreadyExists,
+				domain.ErrInstrumentAlreadyExists,
 			)
 		}