Aramco is the world’s largest oil company, but when it sells shares next year its foray into renewables is what may lure investors who would otherwise be forced to stay away.

Saudi Arabian Oil Co., as it is formally called, is considering investments of as much as $5 billion in renewable energy, part of the kingdom’s effort to reduce the amount of oil feeding domestic energy needs.

That program and signs that King Salman’s government is finally making good on its vows to dramatically expand use of photovoltaics underpin the credibility of Aramco’s embrace of environmental and sustainability goals, measures that investors increasingly are looking for.

“They immediately open themselves up to a larger pool of investors,” said Scott Gehsmann, partner at the deal advisory service of the accounting and consulting firm PwC. “If a company is looking at raising capital, they typically must have a strategy around sustainability. If they don’t have one, it can be perceived as a negative.”

Whether greening Aramco’s IPO would boost the value of the offering is an open question, one clouded the debate over how much investors will pay and whether the renewable-energy program unfolds as expected.

Saudi Arabia has said it thinks Aramco is worth more than $2 trillion. It produces about 10 million barrels of crude a day, about as much as China consumes. Wood Mackenzie Ltd. puts the value at more like $400 billion, clients who attended a private meeting at the oil consultant said last month. The Saudi government is hoping to raise about $100 billion from its initial share sale. It may tender about 5 percent of the company sometime in 2018.

Regardless, drawing in a bigger group of investors requires both better environmental and social governance disclosures and the start of strategy to deal with limits on fossil-fuel pollution coming from the United Nations climate deal signed in Paris in 2015.

Institutional investors with $60 trillion under management have signed up to the Principles for Responsible Investment, pledging to incorporate environmental, social and governance factors, known as ESG, into their investment decisions.

“It’s changing how companies talk to the market and changing how companies govern themselves,” said Steve Waygood, chief responsibility investment officer at Aviva Plc, a London-based insurer. “It’s also changing security analysis. Our fund managers and analysts are completely comfortable talking about ESG as a category of risk today in a way they weren’t 10 years ago.”

Companies from Exxon Mobil Corp. to Royal Dutch Shell Plc have responded to that pressure, releasing ESG data about everything from their carbon emissions to how many women they employ in senior posts. In 2014, 75 percent of those listed on the S&P 500 index released sustainability reports, according to a PwC study. The primary driver of the investor interest was risk mitigation, the study showed.

Aramco still seems to lack transparency and didn’t respond to the latest survey by the CDP, a group that asks companies to report on their ESG data. A spokesperson for the company declined to comment for this story, saying Aramco doesn’t respond to “rumors or speculation.”

For Aramco, the renewables and ESG programs help expand the number of investors who could take a piece of the IPO. Saudi ministries and companies are having to play catch-up to put in place those programs, according to Navi Brar, head of advisory for the Middle East and Africa at AccountAbility.

“Saudi companies and government entities have come to us and said, ‘How do we get our ESG performance up to a level that puts us on a level playing field globally so that investors don’t shy away from us?” said Brar, who advises officials and businesses in Riyadh. “That has been something that we’ve seen, and I would expect investors to ask for such disclosures from Aramco as well.”

The kingdom’s renewables program has gathered pace since the surprise announcement in January 2016 about Aramco’s plan for an IPO. At the start of this year, Energy Minister Khalid Al-Falih announced a target to invest $30 billion to $50 billion in a “massive” renewable energy program, calling for 10 gigawatts of solar and wind power by 2023.

Part of the push is coming from ministers, who since 2012 have become increasingly vocal about their need to diversify the economy away from its near-complete dependence on oil. That discussion culminated last April with Vision 2030, a program championed by Deputy Crown Prince Mohammed bin Salman to open the kingdom to use oil wealth to build capabilities in other industries from banking to tourism and even entering solar-panel manufacturing.

In February, the government invited tenders for its first major wind and solar projects, scheduling a decision in April, although it has since suspended the project. Last month, it invited banks including HSBC Holdings Plc, JPMorgan Chase & Co. and Credit Suisse Group AG to pitch for a role in helping Aramco identify renewable acquisition targets.

Aramco plans to spend about $300 billion in capital expenditures through to 2025. The funds it may allocate to clean energy deals would make up 1.7 percent of the total.

Other oil majors are also dipping their toes into clean energy. Shell is part of a consortium that will build two offshore wind farms in the Dutch North Sea. Total SA has invested in San Jose, California-based SunPower Corp. since 2011 and spent $1.1 billion to acquire battery maker Saft Groupe SA last May.

“Their futures depend on it,” said Rick Wheatley, head of leadership and innovation at Xynteo Ltd., a consultant that advises Royal Dutch Shell Plc, Statoil ASA and Eni SpA on sustainability and long-term planning. “If they want to survive and be meaningful and profitable businesses in 30 to 40 years, they have to.”