MasterCard Inc. is expanding its stake in Strategic Payments Services, a major player in Australia’s electronics payment processing services market. Purchase-based MasterCard said it has signed an agreement that will allow it to own 52.5 percent of Strategic Payments Services, whose clients include Australia’s largest independent network of automated teller machines.

U.S. RE, a Pearl River-based financial services and reinsurance brokerage firm, said that it will expand in Brazil by opening a reinsurance broker subsidiary in Sao Paulo. The new company, U.S. RE do Brasil Corretora de Resseguros, Ltda. will offer all categories of reinsurance coverage to insurers in Brazil. Reinsurance is insurance purchased by insurers from other insurers as a protection against losses.

JW Tumbles recently opened a children’s gym at 624 East Boston Post Road in Mamaroneck. The business offers classes and enrichment programs for children children ages 4 months to 9 years. Other services at JW Tumbles include birthday parties, Kids Night Out and camps. JW Tumbles also operates a second children’s gym in Rye.

AT&T Mobility said that it plans to add new cell sites in Westchester, Putnam and Rockland counties this year to improve its network in the region.

The improvements will help AT&T accomodate a growing demand for advanced wireless data devices and services.

The company said the new cell sites are expected to improve service in Westchester communities of Croton-on-Hudson, Yonkers, Elmsford, Scarsdale and Hartsdale; the Putnam communities of Mahopac, Brewster, and Carmel; and the Rockland communities of Nyack, Monsey and Haverstraw. “Our number one priority in 2009 is to continue to enhance the wireless network so our customers have a top notch experience every time they make a call, send a text or check an e-mail on their AT&T Mobility device,” said Tom DeVito, vice president and general manager for AT&T Mobility in New York and New Jersey.

Guaranteed Home Mortgage Co. Inc., a White Plains-based residential mortgage investment and banking company, said that it has opened 12 new branches and hired 100 new loan officers during the past three months.

The expansion included new locations in Connecticut, Florida, Georgia, Michigan, New Jersey, New York, Ohio and Tennessee. The company estimated that it will gain new sales volumes of $37 million per month as a result of the expansion.

The Center for Wound Healing Inc., a Tarrytown-based operator of wound care treatment centers, said that it has opened it has opened its 36th treatment center. The 2,900-square-foot Jameson Hospital Center for Wound Healing in New Castle, Pa., will treat chronic wounds, including those caused by diabetes, radiation and complications from surgery.

Grand Lux Realty recently opened a new office at 15 Armonk Rd. in Mt. Kisco. The company’s president, Michael Levy has over 23 years of experience in the real estate field. The agency said it has sold more than $35 million of real estate since the company started more than two years ago.

Stark Business Solutions, which leases ready-to-go offices to small businesses, is expanding in southern Westchester County with a new office in Scarsdale Village. The 10,000-square-feet site at 2 Overhill Road will be ready for tenants to move in on Feb. 1. Stark also operates sites in White Plains, Mount Kisco and Harrison.

Starwood Hotels & Resorts Worldwide Inc., the White Plains-based operator of the Sheraton and Westin chains, is pushing ahead with ambitious expansion plans that include opening 100 new hotels this year.

The company also has established goals to expand its total hotel network by more than 40 percent during the next five years.

The expansion comes at a time when Starwood and other lodging companies are battling a global economic slump. Hotel occupancy has suffered as business and leisure travelers cut back on trips. But despite the tough economy that has contributed to a 59 percent drop in Starwood’s stock price during the past year, the company is not putting its long-term investments on hold.

One key milestone in 2009 will be the opening of the company’s 1,000th hotel.

“By working closely with our development partners, we are able to open high caliber, best-in-class hotels around the world, even during challenging economic times,” Simon Turner, president of global development at Starwood, said in a written statement.

Starwood executives outlined the growth plans today at the American Lodging Investment Summit in San Diego.

International markets, which have been growing faster than the United States in recent years, remain a major focus for Starwood. Sixty percent of the 400 hotels in Starwood’s development pipeline are in international markets.

The “new hotels will further position Starwood and its development partners for long term growth and success,” Turner said.

Revitalizing the Sheraton brand will remain a major focus for Starwood in 2009. As part of a $4 billion revitalization program, Sheraton expects to open 18 hotels in major destinations, including New York City; San Juan, Puerto Rico; Istanbul, Turkey; Prague, Czech Republic; and Qiandao, China. The brand is also scheduled to complete $1.3 billion in renovations at nearly 100 existing hotels.

At Westin Hotels & Resorts, 11 hotels are expected to open this year in Montreal, Mumbai, Shanghai, Mexico City, Houston and other major cities. W Hotels, a Starwood brand that is celebrating its 10th anniversary, expects 13 new properties will debut this year.

Verizon Wireless became the nation’s largest cell phone company yesterday after completing its $5.9 billion buyout of Alltel Corp. from Atlantis Holdings LLC.

The deal, originally announced in June, expands Verizon Wireless’ network by 12.9 million customers to 83.7 million customers nationally. Verizon Wireless, which operates a regional headquarters in Orangeburg, said that it will divest 2.1 million customers in coming months to meet federal regulatory requirements for the buyout.

Hudson Valley Bank of Yonkers said that it has received approval from the Office of the Comptroller of the Currency to open a branch in Milford, Conn. The branch is expected to open the second quarter. The bank operates 30 branches in Westchester, Rockland, the Bronx, Manhattan, Queens, Brooklyn and Fairfield County, Conn.

Hudson Valley Bank, a Yonkers-based bank with $2.4 billion in assets, has expanded its presence in Connecticut with the opening of a new branch in the town of Fairfield. Hudson Valley now operates four branches in the state and plans to open additional branches in lower Connecticut next year. The bank’s 30-branch footprint also includes offices in Westchester, Rockland, the Bronx, Manhattan, Queens and Brooklyn.

OpenGate Marketing Communications, a Nyack-based public relations agency, said that it has been hired by the U.S. divisions of three Asian companies to help market their products.

Those clients include New York-based International Beverage USA, a division of Thai Bev, and Rockleigh, N.J.-based True World Restaurant Group, the U.S. division of a Japanese-run fish distributor. OpenGate has also created a new watch and sunglasses brand called Cymbol for the U.S. division of a mainland China manufacturer.

The Center for Wound Healing Inc., a Tarrytown-based manager of wound care treatment centers, said that it recently opened its 35th facility at Pottstown Memorial Medical Center in Pottstown, Pa. The 2,500 square foot center will treat chronic wounds, including those caused by diabetes, vascular disease and trauma.

Gateway Energy Services Corporation, a Montebello-based supplier of electricity and natural gas, is expanding in Canada after receiving regulatory approval to do business in the province of Ontario.

Gateway already provides natural gas and electricity to residential and business customers in 26 markets in six states and the District of Columbia.

“We believe that Ontario is the natural next step in Gateway’s expansion,” Steven J. Maslak, president and chief executive officer of Gateway Energy, said in a written statement. “Thanks to the diligence of Canadian regulators, consumers in this market are well educated about their choices. We are confident that they will appreciate what we’ve got to offer.”

The company said that its Canadian subsidiary, Gateway Energy Services Ltd., received a gas marketer licence from the Ontario Energy Board. Gateway will start a sales campaign directed at commercial customers in Ontario later this month.

Prudential Rand Realty of New City recently bought Kahn Inc., Realtors. Kahn has operated a real estate business in Newburgh for more than 40 years.

As part of the transaction, Prudential Rand will move out of its office in New Windsor and relocate to the 4,700-square-foot Kahn Realtors office in Newburgh. The combined office will have 50 agents, including Kahn’s former staff of 12.

Terms of the transaction were not disclosed.

Stony Point Flowers, which has operated a shop in Rockland County for more than 30 years, recently opened an Internet shopping site. Customer can purchase flowers from the shop at http://www.stonypointnyflowers.com. The shop is affiliated with FlowerShopNetwork.com, an Internet directory designed to help consumers find florists in the area where they need to send flowers.

Endurance Reinsurance Corp. has expanded its presence at at 333 Westchester Avenue in White Plains. The company agreed to lease an additional 5,300 square feet at the complex. That brings its total space to more than 45,000 square feet.

A new Starbucks has opened in New City at 83 S. Main St. The 1,200-square-foot store is in space formerly occupied Friendly’s restaurant. The café, which employs about 22 workers, has been open about six weeks.

Pomona in Rockland County and Yorktown in Westchester County join a list of 138 New York municipalities that have granted television franchises to Verizon Communications Inc. Verizon’s video service is delivered over a fiber-optic network into customers’ homes. The service, known as FiOS TV, offers up to 100 high-definition channels in the New York market and access to more than 11,000 video-on-demand titles.