diff --git a/app/models/account.rb b/app/models/account.rb
index 4421a690..fb074f5e 100644
--- a/app/models/account.rb
+++ b/app/models/account.rb
@@ -1,4 +1,6 @@
 class Account < ApplicationRecord
+  InvalidBalanceError = Class.new(StandardError)
+
   include Syncable, Monetizable, Chartable, Linkable, Enrichable
   include AASM
 
@@ -15,7 +17,7 @@ class Account < ApplicationRecord
   has_many :holdings, dependent: :destroy
   has_many :balances, dependent: :destroy
 
-  monetize :balance, :cash_balance
+  monetize :balance, :cash_balance, :non_cash_balance
 
   enum :classification, { asset: "asset", liability: "liability" }, validate: { allow_nil: true }
 
@@ -126,6 +128,87 @@ class Account < ApplicationRecord
     Account::BalanceUpdater.new(self, balance:, currency:, date:, notes:).update
   end
 
+  def update_current_balance(balance:, cash_balance:)
+    raise InvalidBalanceError, "Cash balance cannot exceed balance" if cash_balance > balance
+
+    if opening_anchor_valuation.present? && valuations.where(kind: "recon").empty?
+      adjust_opening_balance_with_delta(balance:, cash_balance:)
+    else
+      reconcile_balance!(balance:, cash_balance:, date: Date.current)
+    end
+  end
+
+  def reconcile_balance!(balance:, cash_balance:, date:)
+    raise InvalidBalanceError, "Cash balance cannot exceed balance" if cash_balance > balance
+    raise InvalidBalanceError, "Linked accounts cannot be reconciled" if linked?
+
+    existing_valuation = valuations.joins(:entry).where(kind: "recon", entry: { date: Date.current }).first
+
+    if existing_valuation.present?
+      existing_valuation.update!(
+        balance: balance,
+        cash_balance: cash_balance
+      )
+    else
+      entries.create!(
+        date: date,
+        name: Valuation::Name.new("recon", self.accountable_type),
+        amount: balance,
+        currency: self.currency,
+        entryable: Valuation.new(
+          kind: "recon",
+          balance: balance,
+          cash_balance: cash_balance
+        )
+      )
+    end
+  end
+
+  def adjust_opening_balance_with_delta(balance:, cash_balance:)
+    delta = self.balance - balance
+    cash_delta = self.cash_balance - cash_balance
+
+    set_or_update_opening_balance!(
+      balance: balance - delta,
+      cash_balance: cash_balance - cash_delta
+    )
+  end
+
+  def set_or_update_opening_balance!(balance:, cash_balance:, date: nil)
+    # A reasonable start date for most accounts to fill up adequate history for graphs
+    fallback_opening_date = 2.years.ago.to_date
+
+    raise InvalidBalanceError, "Cash balance cannot exceed balance" if cash_balance > balance
+
+    transaction do
+      if opening_anchor_valuation
+        opening_anchor_valuation.update!(
+          balance: balance,
+          cash_balance: cash_balance
+        )
+
+        opening_anchor_valuation.entry.update!(amount: balance)
+        opening_anchor_valuation.entry.update!(date: date) unless date.nil?
+
+        opening_anchor_valuation
+      else
+        entry = entries.create!(
+          date: date || fallback_opening_date,
+          name: Valuation::Name.new("opening_anchor", self.accountable_type),
+          amount: balance,
+          currency: self.currency,
+          entryable: Valuation.new(
+            kind: "opening_anchor",
+            balance: balance,
+            cash_balance: cash_balance,
+          )
+        )
+
+        entry.valuation
+      end
+    end
+  end
+
   def start_date
     first_entry_date = entries.minimum(:date) || Date.current
     first_entry_date - 1.day
@@ -153,4 +236,20 @@ class Account < ApplicationRecord
   def long_subtype_label
     accountable_class.long_subtype_label_for(subtype) || accountable_class.display_name
   end
+
+  # For depository accounts, this is 0 (total balance is liquid cash)
+  # For all other accounts, this represents "asset value" or "debt value"
+  # (i.e. Investment accounts would refer to this as "holdings value")
+  def non_cash_balance
+    balance - cash_balance
+  end
+
+  private
+    def opening_anchor_valuation
+      valuations.opening_anchor.first
+    end
+
+    def current_anchor_valuation
+      valuations.current_anchor.first
+    end
 end
diff --git a/app/models/family.rb b/app/models/family.rb
index 1f35488f..2a9fc553 100644
--- a/app/models/family.rb
+++ b/app/models/family.rb
@@ -116,4 +116,74 @@ class Family < ApplicationRecord
   def self_hoster?
     Rails.application.config.app_mode.self_hosted?
   end
+
+  def create_property_account!(name:, current_value:, purchase_price: nil, purchase_date: nil, currency: nil)
+    Family.transaction do
+      property = accounts.create!(
+        name: name,
+        balance: current_value,
+        cash_balance: 0,
+        currency: currency.presence || self.currency,
+        accountable: Property.new
+      )
+
+      property.set_or_update_opening_balance!(
+        balance: purchase_price || 0,
+        cash_balance: 0,
+        date: purchase_date
+      )
+
+      property
+    end
+  end
+
+  def create_vehicle_account(current_value:, purchase_price: nil, purchase_date: nil, currency: nil)
+    # TODO
+  end
+
+  def create_depository_account(current_balance:, opening_date: nil, currency: nil)
+    # TODO
+  end
+
+  # Investment account values are built up by adding holdings / trades, not by initializing a "balance"
+  def create_investment_account(currency: nil)
+    # TODO
+  end
+
+  def create_other_asset_account(current_value:, purchase_price: nil, purchase_date: nil, currency: nil)
+    # TODO
+  end
+
+  def create_other_liability_account(current_debt:, original_debt: nil, origination_date: nil, currency: nil)
+    # TODO
+  end
+
+  # For now, crypto accounts are very simple; we just track overall value
+  def create_crypto_account(current_value:, currency: nil)
+    # TODO
+  end
+
+  def create_credit_card_account(current_debt:, opening_date: nil, currency: nil)
+    # TODO
+  end
+
+  def create_loan_account(current_principal:, original_principal: nil, origination_date: nil, currency: nil)
+    # TODO
+  end
+
+  def link_depository_account
+    # TODO
+  end
+
+  def link_investment_account
+    # TODO
+  end
+
+  def link_credit_card_account
+    # TODO
+  end
+
+  def link_loan_account
+    # TODO
+  end
 end
diff --git a/test/models/account_test.rb b/test/models/account_test.rb
index c8eb9749..5cb933d8 100644
--- a/test/models/account_test.rb
+++ b/test/models/account_test.rb
@@ -31,4 +31,195 @@ class AccountTest < ActiveSupport::TestCase
     assert_equal "Investments", account.short_subtype_label
     assert_equal "Investments", account.long_subtype_label
   end
+
+  # Currency updates earn their own method because updating an account currency incurs
+  # side effects like recalculating balances, etc.
+  test "can update the account currency" do
+    @account.update_currency("EUR")
+
+    assert_equal "EUR", @account.currency
+  end
+
+  # If a user has an opening balance (valuation) for their manual account and has 1+ transactions, the intent of
+  # "updating current balance" typically means that their start balance is incorrect. We follow that user intent
+  # by default and find the delta required, and update the opening balance so that the timeline reflects this current balance
+  #
+  # The purpose of this is so we're not cluttering up their timeline with "balance reconciliations" that reset the balance
+  # on the current date. Our goal is to keep the timeline with as few "Valuations" as possible.
+  #
+  # If we ever build a UI that gives user options, this test expectation may require some updates, but for now this
+  # is the least surprising outcome.
+  test "when manual account has opening valuation and transactions, adjust opening balance directly with delta" do
+    account = @family.accounts.create!(
+      name: "Test",
+      balance: 900, # the balance after opening valuation + transaction have "synced" (1000 - 100 = 900)
+      cash_balance: 900,
+      currency: "USD",
+      accountable: Depository.new
+    )
+
+    account.entries.create!(
+      date: 1.year.ago.to_date,
+      name: "Test opening valuation",
+      amount: 1000,
+      currency: "USD",
+      entryable: Valuation.new(
+        kind: "opening_anchor",
+        balance: 1000,
+        cash_balance: 1000
+      )
+    )
+
+    account.entries.create!(
+      date: 10.days.ago.to_date,
+      name: "Test expense transaction",
+      amount: 100,
+      currency: "USD",
+      entryable: Transaction.new
+    )
+
+    # What we're asserting here:
+    # 1. User creates the account with an opening balance of 1000
+    # 2. User creates a transaction of 100, which then reduces the balance to 900 (the current balance value on account above)
+    # 3. User requests "current balance update" back to 1000, which was their intention
+    # 4. We adjust the opening balance by the delta (100) to 1100, which is the new opening balance, so that the transaction
+    #    of 100 reduces it down to 1000, which is the current balance they intended.
+    assert_equal 1, account.valuations.count
+    assert_equal 1, account.transactions.count
+
+    # No new valuation is appended; we're just adjusting the opening valuation anchor
+    assert_no_difference "account.entries.count" do
+      account.update_current_balance(balance: 1000, cash_balance: 1000)
+    end
+
+    opening_valuation = account.valuations.first
+
+    assert_equal 1100, opening_valuation.balance
+    assert_equal 1100, opening_valuation.cash_balance
+  end
+
+  # If the user has a "recon valuation" already (i.e. they applied a "balance override"), the most accurate thing we can do is append
+  # a new recon valuation to the current day (i.e. "from this day forward, the balance is X"). Any other action risks altering the user's view
+  # of their balance timeline and makes too many assumptions.
+  test "when manual account has 1+ reconciling valuations, append a new recon valuation rather than adjusting opening balance" do
+    account = @family.accounts.create!(
+      name: "Test",
+      balance: 1000,
+      cash_balance: 1000,
+      currency: "USD",
+      accountable: Depository.new
+    )
+
+    account.entries.create!(
+      date: 1.year.ago.to_date,
+      name: "Test opening valuation",
+      amount: 1000,
+      currency: "USD",
+      entryable: Valuation.new(
+        kind: "opening_anchor",
+        balance: 1000,
+        cash_balance: 1000
+      )
+    )
+
+    # User is "overriding" the balance to 1200 here
+    account.entries.create!(
+      date: 30.days.ago.to_date,
+      name: "First manual recon valuation",
+      amount: 1200,
+      currency: "USD",
+      entryable: Valuation.new(
+        kind: "recon",
+        balance: 1200,
+        cash_balance: 1200
+      )
+    )
+
+    assert_equal 2, account.valuations.count
+
+    # Here, we assume user is once again "overriding" the balance to 1400
+    account.update_current_balance(balance: 1400, cash_balance: 1400)
+
+    most_recent_valuation = account.valuations.joins(:entry).order("entries.date DESC").first
+
+    assert_equal 3, account.valuations.count
+    assert_equal 1400, most_recent_valuation.balance
+    assert_equal 1400, most_recent_valuation.cash_balance
+  end
+
+  # Updating "current balance" for a linked account is a pure system operation that manages the "current anchor" valuation
+  test "updating current balance for linked account modifies current anchor valuation" do
+    # TODO
+  end
+
+  # A recon valuation is an override for a user to "reset" the balance from a specific date forward.
+  # This means, "The balance on X date is Y", which is then used as the new starting point to apply transactions against
+  test "manual accounts can add recon valuations at any point in the account timeline" do
+    assert_equal 1, @account.valuations.count
+
+    @account.reconcile_balance!(balance: 1000, cash_balance: 1000, date: 2.days.ago.to_date)
+
+    assert_equal 2, @account.valuations.count
+
+    most_recent_valuation = @account.valuations.joins(:entry).order("entries.date DESC").first
+
+    assert_equal 1000, most_recent_valuation.balance
+    assert_equal 1000, most_recent_valuation.cash_balance
+  end
+
+  # While technically valid and possible to calculate, "recon" valuations for a linked account rarely make sense
+  # and add complexity. If the user has linked to a data provider, we expect the provider to be responsible for
+  # delivering the correct set of transactions to construct the historical balance
+  test "recon valuations are invalid for linked accounts" do
+    linked_account = accounts(:connected)
+
+    assert_raises Account::InvalidBalanceError do
+      linked_account.reconcile_balance!(balance: 1000, cash_balance: 1000, date: 2.days.ago.to_date)
+    end
+  end
+
+  test "sets or updates opening balance" do
+    Entry.destroy_all
+
+    assert_equal 0, @account.entries.valuations.count
+
+    # Creates non-existent opening valuation
+    @account.set_or_update_opening_balance!(
+      balance: 2000,
+      cash_balance: 2000,
+      date: 2.days.ago.to_date
+    )
+
+    opening_valuation_entry = @account.entries.first
+
+    assert_equal 2000, opening_valuation_entry.amount
+    assert_equal 2.days.ago.to_date, opening_valuation_entry.date
+    assert_equal 2000, opening_valuation_entry.valuation.balance
+    assert_equal 2000, opening_valuation_entry.valuation.cash_balance
+
+    # Updates existing opening valuation
+    @account.set_or_update_opening_balance!(
+      balance: 3000,
+      cash_balance: 3000
+    )
+
+    opening_valuation_entry = @account.entries.first
+
+    assert_equal 3000, opening_valuation_entry.amount
+    assert_equal 2.days.ago.to_date, opening_valuation_entry.date
+    assert_equal 3000, opening_valuation_entry.valuation.balance
+    assert_equal 3000, opening_valuation_entry.valuation.cash_balance
+  end
+
+  # While we don't allow "recon" valuations for a linked account, we DO allow opening balance updates. This is because
+  # providers rarely give 100% of the transaction history (usually cuts off at 2 years), which can misrepresent the true
+  # "opening date" on the account and obscure longer net worth historical graphs. This is an *optional* way for the user
+  # to get their linked account histories "perfect".
+  test "can update the opening balance and date for a linked account" do
+    # TODO
+  end
+
+  test "can update the opening balance and date for a manual account" do
+    # TODO
+  end
 end
diff --git a/test/models/family_test.rb b/test/models/family_test.rb
index 0229aa6e..07390db5 100644
--- a/test/models/family_test.rb
+++ b/test/models/family_test.rb
@@ -4,6 +4,69 @@ class FamilyTest < ActiveSupport::TestCase
   include SyncableInterfaceTest
 
   def setup
-    @syncable = families(:dylan_family)
+    @syncable = @family = families(:dylan_family)
+  end
+
+  test "creates manual property account" do
+    account = @family.create_property_account!(
+      name: "My House",
+      current_value: 450000,
+      purchase_price: 400000,
+      purchase_date: 1.year.ago.to_date
+    )
+
+    valuations = account.valuations
+    assert_equal 1, valuations.count
+    assert_equal "opening_anchor", valuations.first.kind
+    assert_equal 400000, valuations.first.balance
+    assert_equal 0, valuations.first.cash_balance
+
+    assert_equal "My House", account.name
+    assert_equal 450000, account.balance
+    assert_equal 0, account.cash_balance
+  end
+
+  test "creates manual vehicle account" do
+    # TODO
+  end
+
+  test "creates manual depository account" do
+    # TODO
+  end
+
+  test "creates manual investment account" do
+    # TODO
+  end
+
+  test "creates manual other asset or liability account" do
+    # TODO
+  end
+
+  test "creates manual crypto account" do
+    # TODO
+  end
+
+  test "creates manual credit card account" do
+    # TODO
+  end
+
+  test "creates manual loan account" do
+    # TODO
+  end
+
+  test "creates linked depository account" do
+    # TODO
+  end
+
+  test "creates linked investment account" do
+    # TODO
+  end
+
+  test "creates linked credit card account" do
+    # TODO
+  end
+
+  test "creates linked loan account" do
+    # TODO
   end
 end