On Jan. 31, Wall Street’s eyes and ears will all be on ExxonMobil. For the first time in more than a decade, America’s largest energy company is expected to admit it owns less than it has stated. Much less, actually. Exxon may write down up to 20 percent of its oil assets.

This is important not only because of the scale – analysts estimate about 4.6 billion barrels will be written down. Exxon has been reluctant to reevaluate its oil assets for more than two years now. In 2015, publicly held oil companies around the world, wrote down $222 billion in assets, according to the U.S. Energy Information Administration (EIA). But Exxon’s didn’t budge.

Then, in October, the company’s vice president for investor relations, Jeff Woodbury, said Exxon may have to concede that some of its reserves in North America are currently not profitable to produce – the market expects that the write down will appear on the company’s financial statements for the fourth quarter of 2016, due Jan. 31. These include the company’s assets in Alberta, Canada, the world’s third largest oil reserve. Since oil prices started to fall in the second half of 2014, the Canadian oil sand became too expensive to explore. The same happened with many wells in the United States.

A lot of these companies are working in areas that are more expensive to explore, like offshore, deep waters and heavy oil sands. Those assets may have looked promising when prices were higher, but very suddenly they became economically unviable,” said Jeffrey Barron, markets and financial analyst at the EIA.

Every oil and gas company that sells stock in the United States must report any change in its assets to the Securities and Exchange Commission (SEC), following specific rules. One of them defines that the value of oil and gas reserves must be considered using the average price of the commodity during the year. The decline in oil prices was so drastic in 2015 that almost every company had to write down its reserves. It was the largest volume of write downs since at least 2007, Barron said.      

But Exxon has refused to do that. Rex Tillerson, the company’s CEO – which is retiring at the end of 2016 to become Secretary of State – said in an interview that year that Exxon evaluates reserves very conservatively to make sure its projects will still be profitable in a context of low oil prices. This is the official response the company issues every time it is questioned about the reluctance to write downs.

The answer didn’t please New York Attorney General Eric Schneiderman, who started an investigation on the company’s accounting last year. In September, the SEC also started an investigation on the same issue. The question Schneiderman and the SEC are trying to answer is the same many of Exxon’s shareholders are asking: how much does the company actually own?  

“Exxon repeatedly highlighted the strength of its business model and its transparency and reporting integrity, particularly with regard to its oil and gas reserves and the value of those reserves,” wrote the attorneys of Pedro Ramirez Jr., a shareholder leading a class action against the company. “Exxon’s public statements were materially false and misleading.”

Ramirez Jr. is one of many investors who felt harmed by Exxon’s questionable accounting.

His attorneys filed the lawsuit ten days after the October conference call in which the company admitted it may have to write down assets. He claims Exxon “erased billions of dollars” in stock value by misrepresenting the accounting of its reserves. Shares also fell about 4 percent the week after the information was disclosed.

“We anticipate this issue could continue to be a slight overhang on the stock,” wrote Paul Cheng, equity analyst at Barclays, in a report. “Since the initial news of the New York Attorney General’s probe, Exxon shares have increased 3 percent versus an average of 12 percent for its peers.”

The decline also followed a disappointing third quarter for Exxon. The company reported earnings of $2.7 billion, 38 percent less than the $4.2 billion profit it posted during the same period in 2015.

Shares have recovered the lost value since then, but analysts are considering more losses in the future. Goldman Sachs downgraded Exxon from Buy to Neutral after the third-quarter results, and reduced its share estimates for the next year from $98 to $93.

The situation gets even more complicated for Exxon when considering its climate change controversy. Major oil companies have released studies in the past few years admitting that regulations on carbon emissions may reduce the demand for fossil fuels around the world, affecting the value of their assets. But Exxon estimates the demand for oil will continue to grow until at least 2040.

At the 2016 shareholder meeting, in May, a group of investors led by New York State Comptroller Thomas P. DiNapoli proposed that the company release a detailed report on how climate policies would impact its business. The resolution didn’t pass – which means Exxon won’t have to prepare the report – but it had 38 percent of the votes.

“As shareholders, we want to know that Exxon is doing what is needed to prepare for a future with lower carbon emissions,” DiNapoli said in a press release. “The future success of the company, and its investors, requires Exxon to assess how it will perform as the world changes.”

Jeff Woodbury didn’t mention climate policies as a reason for the write down. During the conference call where the subject came up, he only blamed low oil prices and said the company may be able to explore these assets if prices increase or cost efficiencies are implemented. But oil prices are not expected to increase substantially in the medium term, and exploring Alberta’s oil sands may become even more expensive, since the Canadian government is proposing to charge a price for carbon emissions.

Exxon should be prepared for a hard hit on Jan. 31.