diff --git a/Transactions.md b/Transactions.md
index 5d5beb3..0118123 100644
--- a/Transactions.md
+++ b/Transactions.md
@@ -127,6 +127,48 @@ Where
Which is `P2WPKH(Remote Refund Public Key)`
+## Mutual Closing Transaction
+### Known Values
+ * Local Mutual Closing Public Key: `ECPublicKey`
+ * Local Payout: `CurrencyUnit`
+ * Remote Mutual Closing Public Key: `ECPublicKey`
+ * Remote Payout: `CurrencyUnit`
+ * nLockTime: `UInt32`
+ * DLC Funding Output: `ScriptPubKey`
+ * Fee Rate: `FeeUnit`
+
+Where
+ - After the contract maturity time, Mutual Closing Transaction is created in cooperation for fee reduction and improvement in privacy
+ - Both `Mutual Closing Public Key`s are 33-byte compressed public keys
+ - `Local Payout = (Contract Execution Transaction Local Payout).value`
+ - `Remote Payout = (Contract Execution Transaction Remote Payout).value`
+ - `nLockTime` is in the past (rather than just using 0)
+ - for privacy purposes and also to prevent [fee snipping](https://github.com/zkSNACKs/WalletWasabi/issues/2500)
+ - `DLC Funding Output` is of the form [specified above](#FundingOutputs)
+### Global
+ * nLockTime
+### Inputs
+ * Input Spending(P2WSH(DLC Funding Output))
+### Outputs
+ * ToLocalOutput
+ * ToRemoteOutput
+
+Where
+ - `ToLocalOutput's value is Local Payout + MutualClosingFeeDelta/2`
+ - `ToRemoteOutput's value is Remote Payout + MutualClosingFeeDelta/2`
+ - `MutualClosingFeeDelta = Computed CET Fee + Computed ToLocal Closing Fee - Computed MutualClosing Tx Fee (note that the Mutual Closing Transaction is smaller than any CET)`
+ - `ToLocalOutput`'s script is:
+
+ OP_0
+
+ Which is `P2WPKH(Local Mutual Closing Public Key)`
+
+ - `ToRemoteOutput`'s script is:
+
+ OP_0
+
+ Which is `P2WPKH(Remote Mutual Closing Public Key)`
+
## Closing Transaction (Unilateral)
### Known Values
* Local Unilateral Public Key: `ECPublicKey`