GRESB assurance: investor-grade ESG data

In today's real estate and infrastructure markets, sustainability performance is a key factor influencing investor decisions, asset value, financing opportunities, and corporate reputation.

Investors often rely on GRESB assessments to evaluate ESG performance, and GRESB awards points for data that has been independently assured. As a result, the credibility of underlying sustainability data has become more important than ever.

Organisations therefore face the challenge of demonstrating that the information underpinning their sustainability disclosures is accurate, traceable, and supported by robust evidence. This is where GRESB assurance can create significant value.

What is GRESB assurance, and why does it matter?

GRESB assurance is an independent assessment of an organisation's sustainability data. It uses assurance and verification standards recognised by GRESB. The aim is to provide confidence, not only to the reporters, but to the data users, that submitted information is complete, accurate, and appropriately supported.

The assurance process involves reviewing:

reported information;
supporting evidence;
methodologies; and
reporting processes.

While assurance can contribute to achieving up to 5.5 points within the GRESB Management Component, its value extends beyond scoring. Effective assurance also helps organisations to:

understand the strengths and weaknesses of their reporting processes;
identify potential risks before submission; and
improve confidence in reported performance.

How does GRESB assurance create value?

The value of assurance evolves over time.

For first-time assurance reporters

The biggest challenge for first-time assurance reporters is often uncertainty. Common questions include:

Is our evidence sufficient to support reported performance?
How reliable is the information received from property managers and other third parties?
Are there gaps in our audit trail?
What happens if issues are identified close to submission deadlines?

These questions frequently reveal inconsistent methodologies, unclear data ownership, incomplete audit trails, and variable information from service providers. Underlying control weaknesses can remain hidden until assurance begins.

Assurance helps these organisations to identify issues early, reduce reporting risk, and build confidence before submission.

For more mature GRESB reporters

For organisations that have completed several assurance cycles, the focus shifts from validation towards efficiency, governance, and continuous improvement.

The key questions being asked become:

How can we reduce assurance effort and cost?
Which controls should be strengthened?
How can we improve the quality of information received from suppliers and managing agents?
How can assurance support wider sustainability reporting requirements?

At this stage, assurance becomes a governance tool. Findings can strengthen controls, improve reporting efficiency, and create more reliable management information throughout the year, not just during the GRESB reporting cycle.

Value across the GRESB reporting chain

GRESB reporting requires collaboration across multiple stakeholders and organisations, each with different responsibilities and priorities. For example:

sustainability teams need confidence that data from internal and external contributors can withstand scrutiny;
fund managers need credible information for investor communications;
asset managers want practical reporting processes that support commercial objectives; and
property managers and service providers need clear evidence requirements.

Independent assurance aligns these perspectives around credible and reliable ESG information. The result is a stronger GRESB submission, improved reporting processes, clearer accountability, and greater confidence in reported outcomes.

How can BIP.Verco help with GRESB assurance?

Whether this is your first GRESB assurance engagement or your fifth, we can provide a streamlined assessment of reported data, methodologies, supporting evidence, and reporting processes.

For first-time assurance engagements, our Assurance Starter Kit helps teams understand assurance expectations, identify evidence gaps early, and align data owners before reporting deadlines.

For more mature reporters, we help improve controls, strengthen governance, and reduce recurring reporting challenges.

We provide assurance and verification using GRESB-recognised standards, including ISSA 5000, AA1000AS and ISO verification frameworks. We tailor these to your objectives and budget. Alongside the assurance opinion or verification statement, our findings help strengthen future reporting cycles, governance, and confidence in ESG data.

We combine deep expertise in ESG assurance, GHG verification, and GRESB reporting with decades of experience supporting real estate and infrastructure investors and operators. Our pragmatic, risk-based approach focuses on helping clients maximise the value of assurance, strengthen reporting credibility, and make every GRESB submission count.

Fill out the form below for more information on our assurance services.

We're also pleased to offer a free, 30-minute conversation with our team if you're considering these services. This can help you establish what you might need and how we can help you meet your goals. Simply get in touch to arrange this.