diff --git a/hledger-lib/hledger_csv.m4.md b/hledger-lib/hledger_csv.m4.md
index 814a768b4..29a69968a 100644
--- a/hledger-lib/hledger_csv.m4.md
+++ b/hledger-lib/hledger_csv.m4.md
@@ -440,6 +440,7 @@ affects ALL postings.
 
 `balanceN` sets a [balance assertion](journal.html#balance-assertions) amount 
 (or if the posting amount is left empty, a [balance assignment](journal.html#balance-assignments)).
+You may need to adjust this with the [`balance-type` rule](#balance-type).
 
 Finally, `commentN` sets a [comment](journal.html#comments) on the Nth posting. 
 Comments can also contain [tags](journal.html#tags), as usual.
@@ -617,6 +618,28 @@ include categorisation.rules
 ```
 
 
+## `balance-type`
+
+Balance assertions generated by [assigning to balanceN](#posting-field-names)
+are of the simple `=` type by default,
+which is a [single-commodity](https://hledger.org/journal.html#assertions-and-commodities),
+[subaccount-excluding](https://hledger.org/journal.html#assertions-and-subaccounts) assertion.
+You may find the subaccount-including variants more useful, 
+eg if you have created some virtual subaccounts of checking to help with budgeting.
+You can select a different type of assertion with the `balance-type` rule:
+```rules
+# balance assertions will consider all commodities and all subaccounts
+balance-type ==*
+```
+
+Here are the balance assertion types for quick reference:
+```
+=    single commodity, exclude subaccounts
+=*   single commodity, include subaccounts
+==   multi commodity,  exclude subaccounts
+==*  multi commodity,  include subaccounts
+```
+
 # TIPS
 
 ## Rapid feedback