diff --git a/src/reporting/builders.rs b/src/reporting/builders.rs
index 8cd3c11..54717ae 100644
--- a/src/reporting/builders.rs
+++ b/src/reporting/builders.rs
@@ -19,6 +19,8 @@
 use std::collections::HashMap;
 use std::fmt::Display;
 
+use crate::transaction::update_balances_from_transactions;
+
 use super::calculator::{has_step_or_can_build, HasStepOrCanBuild, ReportingGraphDependencies};
 use super::executor::ReportingExecutionError;
 use super::types::{
@@ -319,17 +321,7 @@ impl ReportingStep for GenerateBalances {
 		let mut balances = BalancesAt {
 			balances: HashMap::new(),
 		};
-
-		for transaction in transactions.iter() {
-			for posting in transaction.postings.iter() {
-				// FIXME: Do currency conversion
-				let running_balance =
-					balances.balances.get(&posting.account).unwrap_or(&0) + posting.quantity;
-				balances
-					.balances
-					.insert(posting.account.clone(), running_balance);
-			}
-		}
+		update_balances_from_transactions(&mut balances.balances, transactions.iter());
 
 		// Store result
 		products.insert(
@@ -546,17 +538,7 @@ impl ReportingStep for UpdateBalancesAt {
 		let mut balances = BalancesAt {
 			balances: opening_balances_at.balances.clone(),
 		};
-
-		for transaction in transactions.iter() {
-			for posting in transaction.postings.iter() {
-				// FIXME: Do currency conversion
-				let running_balance =
-					balances.balances.get(&posting.account).unwrap_or(&0) + posting.quantity;
-				balances
-					.balances
-					.insert(posting.account.clone(), running_balance);
-			}
-		}
+		update_balances_from_transactions(&mut balances.balances, transactions.iter());
 
 		// Store result
 		products.insert(
@@ -720,17 +702,7 @@ impl ReportingStep for UpdateBalancesBetween {
 		let mut balances = BalancesBetween {
 			balances: opening_balances.clone(),
 		};
-
-		for transaction in transactions.iter() {
-			for posting in transaction.postings.iter() {
-				// FIXME: Do currency conversion
-				let running_balance =
-					balances.balances.get(&posting.account).unwrap_or(&0) + posting.quantity;
-				balances
-					.balances
-					.insert(posting.account.clone(), running_balance);
-			}
-		}
+		update_balances_from_transactions(&mut balances.balances, transactions.iter());
 
 		// Store result
 		products.insert(
diff --git a/src/reporting/steps.rs b/src/reporting/steps.rs
index b541f4a..ed87930 100644
--- a/src/reporting/steps.rs
+++ b/src/reporting/steps.rs
@@ -24,6 +24,7 @@ use std::fmt::Display;
 use chrono::Datelike;
 
 use crate::reporting::types::{BalancesAt, DateStartDateEndArgs, ReportingProductId, Transactions};
+use crate::transaction::update_balances_from_transactions;
 use crate::util::sofy_from_eofy;
 
 use super::calculator::ReportingGraphDependencies;
@@ -245,17 +246,7 @@ impl ReportingStep for AllTransactionsIncludingRetainedEarnings {
 		let mut balances = BalancesAt {
 			balances: opening_balances.balances.clone(),
 		};
-
-		for transaction in transactions.transactions.iter() {
-			for posting in transaction.postings.iter() {
-				// FIXME: Do currency conversion
-				let running_balance =
-					balances.balances.get(&posting.account).unwrap_or(&0) + posting.quantity;
-				balances
-					.balances
-					.insert(posting.account.clone(), running_balance);
-			}
-		}
+		update_balances_from_transactions(&mut balances.balances, transactions.transactions.iter());
 
 		// Store result
 		products.insert(
diff --git a/src/transaction.rs b/src/transaction.rs
index 5a4c1aa..1220c95 100644
--- a/src/transaction.rs
+++ b/src/transaction.rs
@@ -16,6 +16,8 @@
 	along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */
 
+use std::collections::HashMap;
+
 use chrono::NaiveDateTime;
 
 use crate::QuantityInt;
@@ -42,3 +44,16 @@ pub struct Posting {
 	pub quantity: QuantityInt,
 	pub commodity: String,
 }
+
+pub(crate) fn update_balances_from_transactions<'a, I: Iterator<Item = &'a TransactionWithPostings>>(
+	balances: &mut HashMap<String, QuantityInt>,
+	transactions: I,
+) {
+	for transaction in transactions {
+		for posting in transaction.postings.iter() {
+			// FIXME: Do currency conversion
+			let running_balance = balances.get(&posting.account).unwrap_or(&0) + posting.quantity;
+			balances.insert(posting.account.clone(), running_balance);
+		}
+	}
+}