ISA 510 — Initial Audit Engagements: Opening Balances: Complete Guide

Key Takeaways

ISA 510 addresses the auditor's responsibilities regarding opening balances in an initial audit engagement — either where the prior period was audited by a predecessor auditor or where the prior period was not audited at all.
The auditor's objective is to determine whether opening balances contain misstatements that materially affect the current period's financial statements, and whether appropriate accounting policies have been consistently applied (or changes properly accounted for and disclosed).
Opening balances include not just account balances but also matters requiring disclosure that existed at the beginning of the period — contingencies, commitments, guarantees.
Where a predecessor auditor exists, the incoming auditor should read the prior-year financial statements and the predecessor's report, and may review the predecessor's working papers (subject to professional protocols and the entity's consent).
Where the prior period was not audited, the auditor must perform specific procedures — reviewing records, performing extended substantive procedures, and physically verifying assets where possible.
If the auditor cannot obtain sufficient evidence about opening balances, a qualified opinion or disclaimer of opinion is required. If opening balances contain a material misstatement that is not properly accounted for, a qualified or adverse opinion is required.
If the predecessor's report was modified, the auditor must consider the effect of the underlying matter on the current period's risk assessment.

What is ISA 510?

ISA 510, titled "Initial Audit Engagements — Opening Balances," addresses a challenge unique to first-year audits: the auditor has no first-hand knowledge of whether last year's closing balances — which become this year's opening balances — are correct. Unlike a continuing engagement where the auditor can rely on prior-year work, the initial engagement starts with an evidence gap.

This matters because opening balances directly affect the current period. Beginning inventory flows into cost of sales. Opening retained earnings carry forward the cumulative effect of all prior-period transactions. Opening provisions and accruals reverse in the current period. If the opening balances are wrong, the current-period financial statements are wrong — even if every current-year transaction is correctly recorded.

When Does ISA 510 Apply?

ISA 510 applies in two situations:

Scenario 1: Prior period was audited by a predecessor auditor. The entity has changed auditors. The prior-year financial statements carry an audit opinion from another firm. The incoming auditor must obtain evidence about opening balances without having performed the prior-year audit.

Scenario 2: Prior period was not audited. The entity is being audited for the first time — perhaps because it has grown beyond the audit exemption threshold, has obtained financing that requires an audit, or has been newly incorporated. The prior-year figures have never been examined by an auditor.

The Auditor's Objectives

ISA 510.3 states the objectives:

(a) Obtain sufficient appropriate audit evidence about whether opening balances contain misstatements that materially affect the current period's financial statements.

(b) Determine whether appropriate accounting policies reflected in the opening balances have been consistently applied in the current period, or whether changes are appropriately accounted for and adequately presented and disclosed.

Procedures for Opening Balances

Reading the prior-year financial statements

ISA 510.6 requires the auditor to read the most recent financial statements (if any) and the predecessor auditor's report thereon (if any) for information relevant to opening balances, including disclosures.

Where a predecessor auditor exists

ISA 510.6(a) contemplates the incoming auditor considering whether the predecessor's working papers provide evidence about the opening balances. The practical steps:

Step	What It Involves
Contact the predecessor	With the entity's consent, communicate with the predecessor auditor. Professional ethics require the predecessor to respond to legitimate inquiries.
Review working papers	Subject to the predecessor's agreement (and the entity's consent), review the predecessor's working papers for significant areas — particularly closing procedures, summary of adjustments, and the overall audit approach.
Evaluate the predecessor's competence	Consider the predecessor's professional qualifications, reputation, and regulatory standing. A predecessor with a history of regulatory sanctions may produce less reliable work.
Read the predecessor's report	Identify any modifications, emphases of matter, or other significant observations that affect the opening balances.

The incoming auditor cannot simply rely on the predecessor's work — they must form their own conclusions. The predecessor's working papers provide context and may reduce the extent of additional procedures needed, but they do not substitute for the incoming auditor's own evidence.

Where the prior period was not audited

ISA 510.6(b) requires the auditor to obtain evidence about opening balances through other procedures:

Reviewing the entity's accounting records and other documentation relating to prior periods.
Performing extended substantive procedures on current-period transactions that provide indirect evidence about opening balances — for example, collecting opening receivables during the current period confirms their existence, and clearing opening inventory through cost of sales confirms its approximate valuation.
Physically verifying assets — inspecting fixed assets, counting inventory (if applicable to the opening period), and confirming bank balances.
Reviewing subsequent events that may provide evidence about opening-balance items.

The balance sheet vs. the income statement

An important practical distinction: opening balance sheet items (assets, liabilities, equity) need direct evidence — they carry forward indefinitely if incorrect. Opening income statement items are less problematic because the prior-period income statement is already closed and the balances have been absorbed into retained earnings.

The auditor's primary concern is whether opening balance sheet items are materially misstated — because those misstatements flow directly into the current-period financial statements. For example, if opening inventory is overstated by €100,000, the current-period cost of sales is understated by €100,000 (inflating current-period profit). This is why inventory and receivables at the opening date typically receive the most attention.

Accounting Policy Consistency

ISA 510.6(c) requires the auditor to evaluate whether accounting policies reflected in the opening balances are consistent with those applied in the current period, and whether any changes have been appropriately accounted for and disclosed under the applicable financial reporting framework.

If the entity has changed accounting policies between the prior and current period (e.g., adopted a new IFRS standard, changed depreciation method, changed revenue recognition policy), the auditor must evaluate whether the change and its disclosure comply with the framework and whether the comparative information has been appropriately restated where required.

Modification to the Predecessor's Report

ISA 510.7 requires the auditor, if the predecessor's report contained a modification, to evaluate the effect of the matter that gave rise to the modification when assessing the risks of material misstatement in the current period.

For example:

If the predecessor issued a qualified opinion because they could not attend the physical inventory count, the incoming auditor must consider whether the opening inventory figure is reliable and what evidence is needed to support it.
If the predecessor issued a going concern emphasis of matter, the incoming auditor must evaluate whether that concern persists and affects the current period.
If the predecessor disclaimed an opinion due to scope limitations, the incoming auditor faces a significant evidence gap that may be very difficult to overcome.

Reporting Implications

ISA 510.10–13 sets out the reporting consequences:

Unable to obtain sufficient evidence about opening balances

If the auditor cannot obtain sufficient appropriate audit evidence regarding opening balances:

Express a qualified opinion on the financial statements (if the possible effects are material but not pervasive).
Express a disclaimer of opinion (if the possible effects are material and pervasive — which is more likely for opening balance issues, since they can affect the entire balance sheet and income statement).

Opening balances contain a material misstatement

If the auditor concludes that the opening balances contain a misstatement that materially affects the current period's financial statements, and the misstatement is not appropriately accounted for or disclosed:

Express a qualified opinion (if material but not pervasive).
Express an adverse opinion (if material and pervasive).

Important nuance: balance sheet vs. income statement effects

ISA 510 recognises that the effect of opening balance misstatements may be confined to specific financial statements. A misstatement that affects the balance sheet position may not materially affect the income statement (or vice versa). In such cases, a qualification may apply to some statements but not others.

ISA 510 in Your Jurisdiction

Netherlands. COS 510 follows ISA 510 closely. The NBA provides guidance on communication between predecessor and successor auditors (collegiale toetsing principles). Dutch professional ethics require the predecessor to cooperate with legitimate inquiries from the incoming auditor. AFM inspections examine whether incoming auditors have performed adequate procedures on opening balances and whether the transition between auditors was properly managed.

Germany. IDW PS 510 adapts ISA 510. German practice includes specific protocols for the Prüferwechsel (change of auditor), including the requirement to communicate with the predecessor and the entity's supervisory board. The WPK's inspections focus on whether incoming auditors have obtained adequate evidence about opening balances, particularly for complex areas such as provisions and estimates.

United Kingdom. ISA (UK) 510 is substantively aligned with ISA 510. The FRC has published guidance on communication between predecessor and successor auditors. UK ethical standards require the predecessor to provide access to relevant information (subject to client consent). The FRC's inspections focus on the quality of opening balance procedures in initial engagements.

France. NEP 510 implements ISA 510 within the French statutory framework. The French system of joint audit (co-commissariat aux comptes) for certain entities means that changes of one auditor while the other continues provide a partial continuity of evidence. For complete changes of auditor, the H3C expects comprehensive evidence-gathering procedures on opening balances.

Frequently Asked Questions

Can the auditor rely entirely on the predecessor's work?

No. The incoming auditor must form their own conclusions. The predecessor's working papers provide useful context and may reduce the extent of additional procedures, but the incoming auditor cannot delegate their responsibility for the current-year opinion by relying on someone else's work. The extent to which the predecessor's papers are used depends on the incoming auditor's evaluation of the predecessor's competence and the quality of their work.

What if the predecessor refuses to cooperate?

This is uncommon but can occur. If the predecessor refuses to provide access to working papers or to communicate, the incoming auditor must perform alternative procedures to obtain evidence about opening balances. The refusal itself may be relevant to the risk assessment — it could indicate unresolved issues from the prior engagement.

How much work is needed on opening balances?

This depends on the nature and materiality of the balances, whether the prior period was audited (and by whom), and the assessed risks. Current assets and liabilities (receivables, inventory, accruals) typically require the most attention because they directly affect the current-period income statement. Non-current assets may require less work if the auditor can verify their current existence and condition and roll back to the opening position.

Does ISA 510 apply to recurring audits?

No. ISA 510 applies only to initial audit engagements — where the entity has either changed auditors or is being audited for the first time. In recurring engagements, the auditor already has evidence from the prior-year audit that supports the opening balances.