diff --git a/src/Duempelkas.Infrastructure/Migrations/20260403093901_AllowSharedDisplayIdForTransfers.Designer.cs b/src/Duempelkas.Infrastructure/Migrations/20260403093901_AllowSharedDisplayIdForTransfers.Designer.cs
new file mode 100644
index 0000000..8d5b132
--- /dev/null
+++ b/src/Duempelkas.Infrastructure/Migrations/20260403093901_AllowSharedDisplayIdForTransfers.Designer.cs
@@ -0,0 +1,169 @@
+// <auto-generated />
+using System;
+using Duempelkas.Infrastructure.Persistence;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Migrations;
+using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
+
+#nullable disable
+
+namespace Duempelkas.Infrastructure.Migrations
+{
+    [DbContext(typeof(FinanceDbContext))]
+    [Migration("20260403093901_AllowSharedDisplayIdForTransfers")]
+    partial class AllowSharedDisplayIdForTransfers
+    {
+        /// <inheritdoc />
+        protected override void BuildTargetModel(ModelBuilder modelBuilder)
+        {
+#pragma warning disable 612, 618
+            modelBuilder.HasAnnotation("ProductVersion", "10.0.5");
+
+            modelBuilder.Entity("Duempelkas.Domain.Entities.Account", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("INTEGER");
+
+                    b.Property<decimal>("CarryoverBalance")
+                        .HasColumnType("decimal(18,2)");
+
+                    b.Property<DateTime>("CreatedUtc")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasMaxLength(200)
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("Accounts");
+                });
+
+            modelBuilder.Entity("Duempelkas.Domain.Entities.Entry", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("INTEGER");
+
+                    b.Property<int>("AccountId")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<decimal>("Amount")
+                        .HasColumnType("decimal(18,2)");
+
+                    b.Property<DateTime>("CreatedUtc")
+                        .HasColumnType("TEXT");
+
+                    b.Property<DateTime>("Date")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("DisplayId")
+                        .IsRequired()
+                        .HasMaxLength(20)
+                        .HasColumnType("TEXT");
+
+                    b.Property<bool>("IsDeleted")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("INTEGER")
+                        .HasDefaultValue(false);
+
+                    b.Property<string>("Title")
+                        .IsRequired()
+                        .HasMaxLength(500)
+                        .HasColumnType("TEXT");
+
+                    b.Property<int?>("TransferLinkId")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<int>("Type")
+                        .HasColumnType("INTEGER");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("DisplayId");
+
+                    b.HasIndex("TransferLinkId");
+
+                    b.HasIndex("AccountId", "Date");
+
+                    b.ToTable("Entries");
+                });
+
+            modelBuilder.Entity("Duempelkas.Domain.Entities.TransferLink", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("INTEGER");
+
+                    b.Property<DateTime>("CreatedUtc")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Note")
+                        .HasMaxLength(500)
+                        .HasColumnType("TEXT");
+
+                    b.Property<int>("SourceEntryId")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<int>("TargetEntryId")
+                        .HasColumnType("INTEGER");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("SourceEntryId")
+                        .IsUnique();
+
+                    b.HasIndex("TargetEntryId")
+                        .IsUnique();
+
+                    b.ToTable("TransferLinks");
+                });
+
+            modelBuilder.Entity("Duempelkas.Domain.Entities.Entry", b =>
+                {
+                    b.HasOne("Duempelkas.Domain.Entities.Account", "Account")
+                        .WithMany("Entries")
+                        .HasForeignKey("AccountId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("Duempelkas.Domain.Entities.TransferLink", "TransferLink")
+                        .WithMany()
+                        .HasForeignKey("TransferLinkId")
+                        .OnDelete(DeleteBehavior.Restrict);
+
+                    b.Navigation("Account");
+
+                    b.Navigation("TransferLink");
+                });
+
+            modelBuilder.Entity("Duempelkas.Domain.Entities.TransferLink", b =>
+                {
+                    b.HasOne("Duempelkas.Domain.Entities.Entry", "SourceEntry")
+                        .WithMany()
+                        .HasForeignKey("SourceEntryId")
+                        .OnDelete(DeleteBehavior.Restrict)
+                        .IsRequired();
+
+                    b.HasOne("Duempelkas.Domain.Entities.Entry", "TargetEntry")
+                        .WithMany()
+                        .HasForeignKey("TargetEntryId")
+                        .OnDelete(DeleteBehavior.Restrict)
+                        .IsRequired();
+
+                    b.Navigation("SourceEntry");
+
+                    b.Navigation("TargetEntry");
+                });
+
+            modelBuilder.Entity("Duempelkas.Domain.Entities.Account", b =>
+                {
+                    b.Navigation("Entries");
+                });
+#pragma warning restore 612, 618
+        }
+    }
+}
diff --git a/src/Duempelkas.Infrastructure/Migrations/20260403093901_AllowSharedDisplayIdForTransfers.cs b/src/Duempelkas.Infrastructure/Migrations/20260403093901_AllowSharedDisplayIdForTransfers.cs
new file mode 100644
index 0000000..b9f3d3a
--- /dev/null
+++ b/src/Duempelkas.Infrastructure/Migrations/20260403093901_AllowSharedDisplayIdForTransfers.cs
@@ -0,0 +1,37 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace Duempelkas.Infrastructure.Migrations
+{
+    /// <inheritdoc />
+    public partial class AllowSharedDisplayIdForTransfers : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropIndex(
+                name: "IX_Entries_DisplayId",
+                table: "Entries");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_Entries_DisplayId",
+                table: "Entries",
+                column: "DisplayId");
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropIndex(
+                name: "IX_Entries_DisplayId",
+                table: "Entries");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_Entries_DisplayId",
+                table: "Entries",
+                column: "DisplayId",
+                unique: true);
+        }
+    }
+}
diff --git a/src/Duempelkas.Infrastructure/Migrations/FinanceDbContextModelSnapshot.cs b/src/Duempelkas.Infrastructure/Migrations/FinanceDbContextModelSnapshot.cs
index a6f67c5..54b156a 100644
--- a/src/Duempelkas.Infrastructure/Migrations/FinanceDbContextModelSnapshot.cs
+++ b/src/Duempelkas.Infrastructure/Migrations/FinanceDbContextModelSnapshot.cs
@@ -80,8 +80,7 @@ namespace Duempelkas.Infrastructure.Migrations
 
                     b.HasKey("Id");
 
-                    b.HasIndex("DisplayId")
-                        .IsUnique();
+                    b.HasIndex("DisplayId");
 
                     b.HasIndex("TransferLinkId");
 
diff --git a/src/Duempelkas.Infrastructure/Persistence/Configurations/EntryConfiguration.cs b/src/Duempelkas.Infrastructure/Persistence/Configurations/EntryConfiguration.cs
index c4a9675..66bfd0f 100644
--- a/src/Duempelkas.Infrastructure/Persistence/Configurations/EntryConfiguration.cs
+++ b/src/Duempelkas.Infrastructure/Persistence/Configurations/EntryConfiguration.cs
@@ -10,7 +10,7 @@ public class EntryConfiguration : IEntityTypeConfiguration<Entry>
     {
         builder.HasKey(e => e.Id);
         builder.Property(e => e.DisplayId).IsRequired().HasMaxLength(20);
-        builder.HasIndex(e => e.DisplayId).IsUnique();
+        builder.HasIndex(e => e.DisplayId);
         builder.Property(e => e.Title).IsRequired().HasMaxLength(500);
         builder.Property(e => e.Amount).HasColumnType("decimal(18,2)");
         builder.Property(e => e.Type).HasConversion<int>();
diff --git a/src/Duempelkas.Infrastructure/Services/EntryService.cs b/src/Duempelkas.Infrastructure/Services/EntryService.cs
index f690c9d..2960a62 100644
--- a/src/Duempelkas.Infrastructure/Services/EntryService.cs
+++ b/src/Duempelkas.Infrastructure/Services/EntryService.cs
@@ -63,7 +63,7 @@ public class EntryService : IEntryService
     {
         await using var db = await _dbFactory.CreateDbContextAsync();
 
-        var displayId = await GenerateDisplayIdAsync(db, accountId, date.Year);
+        var displayId = await GenerateDisplayIdAsync(db, date.Year);
 
         var entry = new Entry
         {
@@ -88,12 +88,12 @@ public class EntryService : IEntryService
         await using var db = await _dbFactory.CreateDbContextAsync();
         await using var transaction = await db.Database.BeginTransactionAsync();
 
-        var sourceDisplayId = await GenerateDisplayIdAsync(db, sourceAccountId, date.Year);
+        var transferDisplayId = await GenerateDisplayIdAsync(db, date.Year);
 
         var sourceEntry = new Entry
         {
             AccountId = sourceAccountId,
-            DisplayId = sourceDisplayId,
+            DisplayId = transferDisplayId,
             Type = EntryType.Expense,
             Date = date,
             Title = title,
@@ -103,12 +103,10 @@ public class EntryService : IEntryService
         db.Entries.Add(sourceEntry);
         await db.SaveChangesAsync();
 
-        var targetDisplayId = await GenerateDisplayIdAsync(db, targetAccountId, date.Year);
-
         var targetEntry = new Entry
         {
             AccountId = targetAccountId,
-            DisplayId = targetDisplayId,
+            DisplayId = transferDisplayId,
             Type = EntryType.Income,
             Date = date,
             Title = title,
@@ -234,13 +232,12 @@ public class EntryService : IEntryService
         if (otherEntry.AccountId != newLinkedAccountId)
         {
             otherEntry.AccountId = newLinkedAccountId;
-            otherEntry.DisplayId = await GenerateDisplayIdAsync(db, newLinkedAccountId, date.Year);
         }
 
         await db.SaveChangesAsync();
     }
 
-    private static async Task<string> GenerateDisplayIdAsync(FinanceDbContext db, int accountId, int year)
+    private static async Task<string> GenerateDisplayIdAsync(FinanceDbContext db, int year)
     {
         var prefix = $"{year}-";
         var maxDisplayId = await db.Entries
diff --git a/tests/Duempelkas.Tests/EntryServiceBookingTests.cs b/tests/Duempelkas.Tests/EntryServiceBookingTests.cs
new file mode 100644
index 0000000..34494e4
--- /dev/null
+++ b/tests/Duempelkas.Tests/EntryServiceBookingTests.cs
@@ -0,0 +1,123 @@
+using Duempelkas.Domain.Entities;
+using Duempelkas.Domain.Enums;
+using Duempelkas.Infrastructure.Persistence;
+using Duempelkas.Infrastructure.Services;
+using FluentAssertions;
+using Microsoft.EntityFrameworkCore;
+using Xunit;
+
+namespace Duempelkas.Tests;
+
+public class EntryServiceBookingTests : IDisposable
+{
+    private readonly FinanceDbContext _db;
+    private readonly EntryService _entryService;
+    private readonly string _connectionString = $"Data Source=duempelkas-entry-tests-{Guid.NewGuid():N};Mode=Memory;Cache=Shared";
+
+    public EntryServiceBookingTests()
+    {
+        var options = new DbContextOptionsBuilder<FinanceDbContext>()
+            .UseSqlite(_connectionString)
+            .Options;
+
+        _db = new FinanceDbContext(options);
+        _db.Database.OpenConnection();
+        _db.Database.EnsureCreated();
+
+        var dbFactory = new TestDbContextFactory(options);
+        _entryService = new EntryService(dbFactory);
+    }
+
+    [Fact]
+    public async Task CreateEntry_AssignsSequentialDisplayIds_PerYear()
+    {
+        var accountA = new Account { Name = "Konto A" };
+        var accountB = new Account { Name = "Konto B" };
+        _db.Accounts.AddRange(accountA, accountB);
+        await _db.SaveChangesAsync();
+
+        var first = await _entryService.CreateEntryAsync(accountA.Id, EntryType.Income, new DateTime(2026, 1, 10), "Einnahme A", 100m);
+        var second = await _entryService.CreateEntryAsync(accountB.Id, EntryType.Expense, new DateTime(2026, 1, 11), "Ausgabe B", 20m);
+        var third = await _entryService.CreateEntryAsync(accountA.Id, EntryType.Income, new DateTime(2027, 1, 1), "Neues Jahr", 5m);
+
+        first.DisplayId.Should().Be("2026-001");
+        second.DisplayId.Should().Be("2026-002");
+        third.DisplayId.Should().Be("2027-001");
+    }
+
+    [Fact]
+    public async Task CreateEntry_AfterTransfer_UsesNextDisplayId()
+    {
+        var source = new Account { Name = "Barkasse" };
+        var target = new Account { Name = "Girokonto" };
+        _db.Accounts.AddRange(source, target);
+        await _db.SaveChangesAsync();
+
+        await _entryService.CreateTransferAsync(source.Id, target.Id, new DateTime(2026, 3, 15), "Umbuchung", 500m);
+        var booking = await _entryService.CreateEntryAsync(source.Id, EntryType.Income, new DateTime(2026, 3, 16), "Einzahlung", 50m);
+
+        booking.DisplayId.Should().Be("2026-002");
+    }
+
+    [Fact]
+    public async Task UpdateEntry_UpdatesBookingFields()
+    {
+        var account = new Account { Name = "Konto" };
+        _db.Accounts.Add(account);
+        await _db.SaveChangesAsync();
+
+        var entry = await _entryService.CreateEntryAsync(account.Id, EntryType.Expense, new DateTime(2026, 2, 2), "Alt", 10m);
+
+        await _entryService.UpdateEntryAsync(entry.Id, new DateTime(2026, 2, 3), "Neu", 25m);
+
+        _db.ChangeTracker.Clear();
+        var updated = await _db.Entries.SingleAsync(e => e.Id == entry.Id);
+
+        updated.Date.Should().Be(new DateTime(2026, 2, 3));
+        updated.Title.Should().Be("Neu");
+        updated.Amount.Should().Be(25m);
+    }
+
+    [Fact]
+    public async Task DeleteAndRestoreEntry_TogglesSoftDelete_ForBookingOnly()
+    {
+        var account = new Account { Name = "Konto" };
+        _db.Accounts.Add(account);
+        await _db.SaveChangesAsync();
+
+        var entry = await _entryService.CreateEntryAsync(account.Id, EntryType.Expense, new DateTime(2026, 2, 2), "Buchung", 10m);
+
+        await _entryService.DeleteEntryAsync(entry.Id);
+
+        _db.ChangeTracker.Clear();
+        var deleted = await _db.Entries.SingleAsync(e => e.Id == entry.Id);
+        deleted.IsDeleted.Should().BeTrue();
+
+        await _entryService.RestoreEntryAsync(entry.Id);
+
+        _db.ChangeTracker.Clear();
+        var restored = await _db.Entries.SingleAsync(e => e.Id == entry.Id);
+        restored.IsDeleted.Should().BeFalse();
+    }
+
+    public void Dispose()
+    {
+        _db.Database.CloseConnection();
+        _db.Dispose();
+    }
+
+    private sealed class TestDbContextFactory : IDbContextFactory<FinanceDbContext>
+    {
+        private readonly DbContextOptions<FinanceDbContext> _options;
+
+        public TestDbContextFactory(DbContextOptions<FinanceDbContext> options)
+        {
+            _options = options;
+        }
+
+        public FinanceDbContext CreateDbContext() => new(_options);
+
+        public Task<FinanceDbContext> CreateDbContextAsync(CancellationToken cancellationToken = default)
+            => Task.FromResult(new FinanceDbContext(_options));
+    }
+}
diff --git a/tests/Duempelkas.Tests/TransferServiceTests.cs b/tests/Duempelkas.Tests/TransferServiceTests.cs
index 0ad0c1f..835535e 100644
--- a/tests/Duempelkas.Tests/TransferServiceTests.cs
+++ b/tests/Duempelkas.Tests/TransferServiceTests.cs
@@ -13,11 +13,12 @@ public class TransferServiceTests : IDisposable
     private readonly FinanceDbContext _db;
     private readonly EntryService _entryService;
     private readonly BalanceQueryService _balanceQueryService;
+    private readonly string _connectionString = $"Data Source=duempelkas-transfer-tests-{Guid.NewGuid():N};Mode=Memory;Cache=Shared";
 
     public TransferServiceTests()
     {
         var options = new DbContextOptionsBuilder<FinanceDbContext>()
-            .UseSqlite("Data Source=duempelkas-transfer-tests;Mode=Memory;Cache=Shared")
+            .UseSqlite(_connectionString)
             .Options;
 
         _db = new FinanceDbContext(options);
@@ -52,7 +53,8 @@ public class TransferServiceTests : IDisposable
         var targetEntry = entries.Single(e => e.AccountId == accountB.Id);
         targetEntry.Type.Should().Be(EntryType.Income);
         targetEntry.Amount.Should().Be(100.00m);
-        targetEntry.DisplayId.Should().Be("2026-002");
+        targetEntry.DisplayId.Should().Be("2026-001");
+        targetEntry.DisplayId.Should().Be(sourceEntry.DisplayId);
 
         var links = await _db.TransferLinks.ToListAsync();
         links.Should().HaveCount(1);
@@ -105,6 +107,29 @@ public class TransferServiceTests : IDisposable
         await act.Should().ThrowAsync<InvalidOperationException>();
     }
 
+    [Fact]
+    public async Task UpdateTransfer_ChangeLinkedAccount_KeepsSharedDisplayId()
+    {
+        var source = new Account { Name = "Barkasse" };
+        var initialTarget = new Account { Name = "Girokonto" };
+        var newTarget = new Account { Name = "Sparkonto" };
+        _db.Accounts.AddRange(source, initialTarget, newTarget);
+        await _db.SaveChangesAsync();
+
+        await _entryService.CreateTransferAsync(source.Id, initialTarget.Id, new DateTime(2026, 3, 15), "Umbuchung", 500.00m);
+        var sourceEntry = await _db.Entries.SingleAsync(e => e.AccountId == source.Id);
+
+        await _entryService.UpdateTransferAsync(sourceEntry.Id, newTarget.Id, new DateTime(2026, 3, 16), "Umbuchung angepasst", 550.00m);
+
+        _db.ChangeTracker.Clear();
+
+        var updatedSourceEntry = await _db.Entries.SingleAsync(e => e.AccountId == source.Id);
+        var updatedTargetEntry = await _db.Entries.SingleAsync(e => e.AccountId == newTarget.Id);
+
+        updatedSourceEntry.DisplayId.Should().Be("2026-001");
+        updatedTargetEntry.DisplayId.Should().Be(updatedSourceEntry.DisplayId);
+    }
+
     public void Dispose()
     {
         _db.Database.CloseConnection();
diff --git a/tests/Duempelkas.Tests/YearlyStatementCalculationTests.cs b/tests/Duempelkas.Tests/YearlyStatementCalculationTests.cs
index 9866e0c..b1da5b4 100644
--- a/tests/Duempelkas.Tests/YearlyStatementCalculationTests.cs
+++ b/tests/Duempelkas.Tests/YearlyStatementCalculationTests.cs
@@ -13,11 +13,12 @@ public class BalanceCalculationTests : IDisposable
     private readonly FinanceDbContext _db;
     private readonly BalanceQueryService _balanceQueryService;
     private readonly EntryService _entryService;
+    private readonly string _connectionString = $"Data Source=duempelkas-balance-tests-{Guid.NewGuid():N};Mode=Memory;Cache=Shared";
 
     public BalanceCalculationTests()
     {
         var options = new DbContextOptionsBuilder<FinanceDbContext>()
-            .UseSqlite("Data Source=duempelkas-balance-tests;Mode=Memory;Cache=Shared")
+            .UseSqlite(_connectionString)
             .Options;
 
         _db = new FinanceDbContext(options);