Is the Auction House a global AH in Diablo III?

In the Diablo III Auction House, is it a global AH, or does it only display items from a certain sector that they place you in?

And, is it the same for both real money and gold, or is one global and one is not?

I'd imagine having one large global AH would destroy the market, but if it's sectored, is it a large enough sector?

Solution 1:

All Diablo 3 Auction Houses (both Real Money and gold) are regional, one of the same three regions there are for servers:

The Americas, Asia, and Europe.

Additionally, Hardcore characters are entirely separate from "softcore" characters - this means no trading and a separate shared stash, but it also means a separate pair of auction houses to boot.

Solution 2:

The gold and real money auction houses were closed on March 18, 2014, source.

Q. When will the gold and real-money auction houses be removed from the game?

The gold and real-money auction houses will be shut down on Tuesday, March 18, 2014.