this means that Halo 5 sold less than 1 million copies in 3 days (it was released on 27/10/2015).
Great performance i must say.
You should also consider the digital sales which were next to zero for previous Halo releases....

27th, 28th, 29th, 30th, 31st.

Seems like 5 days to me.

Well i expected it to show a decline, but not this big. It's clear they should give the franchise a rest now. Gears of War won't fair much better i'm afraid.

Poor month for software all round.

MS may have some things to do think over the next few years.

Gears 4 is not Halo, Halo 6 or FPS. What's the correlation?

Kinda hard to compare the game to past entries unit per unit until M$ releases full numbers with as many games get bought digitally now. I think it still did good for the install base size.

That is so much not true.

Respective to expectations, franchise standards and potentially marketing budget aswell, yes. Now if only this would happen with franchises that really need a break, like Assassins Creed.

"The best-selling title of the October 2015 U.S. Games Industry report, Microsoft's Console Software SKU 'Halo 5: Guardians,' sold a combined total of 935K including all Bundle units."

Wow.

So if Halo 5 cannot not help Xbox One, what else can help Xbox One