Marriott International will buy Starwood Hotels & Resorts Worldwide for $12.2 billion to create the world’s largest hotel chain, with top brands including Sheraton, Ritz Carlton and the Autograph Collection. (Andrew Kelly/Reuters)

Marriott International announced Monday that it plans to buy Starwood Hotels & Resorts for $12 billion, creating the world’s largest hotel chain.

But for travelers following the news, one of the biggest questions is: What will this mean for their rewards points?

Starwood, which includes brands such as Westin, Sheraton and W Hotels, has 21 million members in its rewards program, Starwood Preferred Guest. Marriott has 54 million rewards members in its program.

Marriott said Monday it is still figuring out how it would merge the two rewards programs. In a call with investors, Marriott’s chief executive, Arne Sorenson, who will lead the new company, mentioned Starwood’s “strong rewards program” as one of the reasons why Marriott was drawn to Starwood. “Their Starwood Preferred rewards program, we think is very strong and can be even stronger by being part of Marriott,” Sorenson said in an interview with The Washington Post.

It will take some time before the details of the process, which will involve coordinating with third parties such as credit card companies, time share partners and others, are ironed out. But in general, consumers have more options for earning Marriott points and need more points to book a stay, says Zach Honig, editor in chief of ThePointsGuy.com, a Web site that tracks rewards programs. Starwood points are more difficult to earn, but require fewer points to be redeemed, he said.

In addition to earning points by staying at a Marriott hotel or using a Marriott rewards card, travelers have more options for transferring general rewards points earned through a partner credit card over to Marriott, Honig says. While travelers can earn SPG points by staying at a Starwood property, using Uber or making purchases on their SPG credit card from American Express, they have fewer options for transferring rewards points from more general cards.

Eventually, the larger company could create an exchange rate of sorts for each rewards system and have customers transfer their points to the new program. If that were to happen, it’s likely that one Starwood point would be equivalent to multiple Marriott points, Honig says. “I don’t imagine any situation where one Starwood point would be worth one Marriott point when they are combined,” he says.

Either way, travelers have something to gain. Marriott customers would have access to Starwood’s 1,270 properties, including higher-end brands, such as W Hotels. And Starwood customers would now have more options overall for redeeming their points, gaining access to Marriott’s 4,300 properties.

“We want to make sure we’re keeping everybody and if anything, making them even more loyal to this bigger platform than they’ve been to either one of us on a standalone basis,” Sorenson said. “But we’ve got to do the hard work to figure out when exactly, and how exactly, these programs work together.”

Abha Bhattarai contributed to this article.

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