The settlement hinges on the success or failure of the company's appeal of a ruling that found it conspired with publishers to fix prices.
Second phase of price-fixing case against Apple will determine how much the company owes for allegedly conspiring with publishers to eliminate price competition.
Apple would need to pay for an external monitor, sever deals with publishers, and let Amazon and Barnes & Noble link their iOS e-book apps to their respective online stores, among other proposed measures.
The publisher has agreed to terminate its pricing deal with Apple and refrain from making "most favored nation" pricing pacts for five years.
Antitrust lawsuit accused Apple and five book publishers of conspiring to artificially hike prices. Now all but Apple and Macmillan have settled.
The companies signed the agreement with 54 attorneys general across U.S. states, districts, and territories.
The first domino fell last week in the U.S. when the DOJ sued Apple and its publishing partners claiming collusion over pricing of e-books. A class action lawsuit in Canada now claims the same.
The Justice Department may file as early as Wednesday an antitrust lawsuit against the company over how publishers price electronic books, Reuters reports.
Though Apple is not likely to take a major financial hit after the settlement, Amazon stands to gain upward of $1 billion in revenue, one analyst says.
Lawsuit accuses Apple and a group of book publishers of conspiring to fix prices to boost profits and put pressure on Amazon.