NEW YORK (CNNMoney) -- Business leaders are pushing back against an Indiana law that allows them to refuse service to gay people on religious grounds.

The controversial law gives businesses owners who oppose homosexuality for religious reasons the right to turn away gay, lesbian and transgender people. Governor Mike Pence signed the law Thursday, hailing it as a victory for "religious liberty."

But a number of businesses in Indiana and elsewhere -- including Eli Lilly, Salesforce and Yelp -- say the law will make it harder to attract employees and customers to the state. They also say it's unnecessary since Indiana doesn't currently have any laws prohibiting discrimination against gay people.

"In our eyes, the law is entirely unnecessary," said Kevin Brinegar, president of the Indiana Chamber of Commerce. "Passing the law was always going to bring the state unwanted attention."

Eli Lilly and Company, the global drug company based in Indianapolis, said it worked with the chamber of commerce to try to defeat the legislation and called its passage "disappointing." The company employs more than 11,700 workers in Indiana, mostly in Indianapolis.

"We certainly understand the implications this legislation has on our ability to attract and retain employees," said Lilly spokeswoman Janice Chavers. "Simply put, we believe discriminatory legislation is bad for Indiana and for business."

Indianapolis is a major destination for conventions and sporting events, including the upcoming NCAA Final Four college basketball tournament.

"We are especially concerned about how this legislation could affect our student-athletes and employees," NCAA President Mark Emmert said in a statement Thursday.

He said the NCAA will "work diligently" to ensure competitors and visitors at next week's Final Four are not "negatively impacted by this bill." Emmert also said the organization, which is based in Indianapolis, will "closely examine the implications of this bill and how it might affect future events as well as our workforce."

Gen Con, a video game convention that brings tens of millions of dollars to the state each year, said the law would "factor into our decision making on hosting the convention in the state of Indiana in future years."

The convention brings 56,000 people and $50 million to Indiana each year, according to Gen Con CEO Adrian Swartout.

Meanwhile, companies based outside Indiana have suggested they might stop doing business there.

Salesforce CEO Marc Benioff said on Twitter that his company will "dramatically reduce our investments" in Indiana, calling the law an "outrage." Benioff called on other CEOs in the tech industry to follow suit.

Jeremy Stoppelman, CEO of Yelp, criticized Indiana and other states that allow businesses to discriminate against people based on sexual orientation. He said Yelp will "make every effort" to expand its corporate operations in states that do not have such laws on the books.

"These laws set a terrible precedent that will likely harm the broader economic health of the states where they have been adopted, the businesses currently operating in those states and, most importantly, the consumers who could be victimized under these laws."

™ & © 2015 Cable News Network, Inc., a Time Warner Company. All rights reserved.