More than 1,600 companies identified by non-profit platform CDP as having the biggest impact on the environment are not disclosing environmental data, the group said as it launched its latest campaign to get firms to provide the information.

CDP, which has standardized data to allow investors and others to compare corporate performance in areas like climate change, water and deforestation, said 288 financial institutions with around $29 trillion in assets will write to the companies to urge them to disclose the data.

The companies targeted in the 2023 campaign include repeat non-disclosers such as Exxon Mobil, Glencore and Caterpillar, CDP said in a statement.

Exxon said it had a plan "to reduce emissions to support a net-zero future while growing value for our shareholders and stakeholders."

In an emailed statement, the oil giant said between 2016 and end-2021 it had cut the emissions from its own operations and reduced methane emissions intensity from operated assets, and it had hiked the amount it plans to invest on lower-emission initiatives.

Glencore declined to comment. Caterpillar did not respond to a request for comment.

Collectively, the non-disclosers emit an estimated 4,200 megatonnes of CO2 equivalent annually – which CDP said was almost equivalent to the greenhouse-gas emissions of the U.K., the EU and Canada combined.

CDP works to help small groups of lead shareholders target companies and ratchet up pressure on boards to listen, said Claire Elsdon, CDP's joint global director of capital markets.

Financial institutions need the data "to support risk management practices, tracking portfolio alignment to net zero goals and unlocking sustainability-linked opportunities," she said. "These uses can serve to not only safeguard but also boost long-term profitability," Elsdon said.

Since it launched in 2017, CDP has expanded the universe of companies it targets for data disclosure. That has meant the number of non-disclosing companies targeted this year is higher than in its 2022 campaign.

Despite the progress, disclosure remains a problem in high-emitting sectors and getting laggards to submit data will prove tricky, she acknowledged.

Overall, about 50% of companies across sectors disclose environmental data, Elsdon told Reuters.

The 2022 campaign delivered responses from 388 high-impact companies out of nearly 1,500 targeted, and CDP said firms were 2.3 times more likely to disclose if they were directly engaged by financial institutions.

Investors targeting non-dislosing companies this year include Sumitomo Life Insurance, AQR and Legal & General Investment Management.