How much did Microsoft spend developing Gears of War: E-Day? According to information that has emerged in recent hours, the answer could be higher than anyone expected.

A recent report published by Kotaku suggests an investment of more than $500 million, a figure that, if confirmed, would make the game one of the most expensive video games ever made.

The information comes from a “source familiar with Xbox’s business,” who claims that the total cost has exceeded half a billion dollars, without including the marketing budget. To give an idea of the difference, Marvel’s Spider-Man 2 cost around $300 million, just over half that amount.

The rumor has received further support from Christopher Dring of The Game Business, who said he had received confirmation about the size of the investment.

“Yes, so this, from what I’m told, is very true. $500 million. Unbelievable,” Dring wrote.

Jez Corden of Windows Central, however, was more careful. The journalist pointed out that it is not possible to say exactly how much of that amount was spent on Gears of War: E-Day and how much was used for other work by The Coalition, a studio that also provides technical support for several projects within the Xbox ecosystem.

The situation becomes even more complicated when looking at the game’s release strategy. Microsoft decided to keep E-Day as an Xbox console exclusive, even though Jeff Grubb had previously reported that a PS5 version was almost finished before being set aside. Microsoft denied this report, saying that it was not a sudden decision.

As for sales, early estimates suggest that around 230,000 copies were sold during the launch week, along with 1.7 million users who played through Xbox Game Pass. These results are difficult to judge, as the combination of traditional sales and subscriptions makes it far from easy to calculate how much money the game has made.

In other news, The Coalition studio head Mike Crump stated that Gears of War: E-Day establishes a “great foundation” for future entries, meaning the next game will not take another seven years to develop.