(Reuters) - A series of mass shootings in the United States, including one each in Texas and Ohio last month that killed 31 people, once again has revived a national debate on firearms regulation, which in the past has led retailers and other U.S. companies to tighten restrictions on gun sales.

FILE PHOTO: Walmart's logo is seen outside one of the stores in Chicago, Illinois, U.S., November 20, 2018. REUTERS/Kamil Krzaczynski

Last year’s high school shooting in Parkland, Florida, that killed 17 students and educators prompted a number of companies from Walmart to Bank of America to update their policies on firearms.

Here is a list of actions taken and statements made by companies since then, in order of the most recent comments on the issue.

WALMART INC

The largest U.S arms retailer said on Tuesday it would discontinue sales of ammunition for handguns and some assault-style rifles in stores across the United States.

Walmart, which has been under pressure to change its policies on gun sales, also said it would discontinue handgun sales in Alaska, the only state where it still sells these guns.

In February 2018, after the Parkland shooting, it raised the minimum age to purchase firearms to 21 from 18.

It also said then that it would remove items that resemble assault rifles, including non-lethal airsoft guns and toys from its website.

CLOUDFLARE

In August, the U.S. cyber security firm said it would terminate online message board 8chan as a customer after a gunman used the messaging forum prior to the attack at a Walmart store in El Paso, Texas.

LEVI STRAUSS & CO

The jeans maker has been among the more vocal companies against gun violence with its CEO Chip Bergh in 2016 requesting customers not to bring guns into its stores. Bergh said last year the company would donate more than $1 million over the coming years to activists working to “end gun violence in America.”

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KROGER CO

Grocer last year said it would phase out all sales of firearms and ammunition at its Fred Meyer stores, saying it needed to better utilize space in stores. Earlier that year, Kroger said it would stop selling guns to those under the age of 21 following the Parkland shooting.

DICK’S SPORTING GOODS INC

Chief Executive Officer Ed Stack in February 2018 said the company would stop selling all assault-style rifles and high capacity magazines in its stores.

The company at that point also raised the minimum age to purchase firearms to 21 and in March of this year said it would stop selling hunting rifles and ammunition at 125 stores.

CITIGROUP INC

In March last year, the bank implemented rules to make all new retail business clients, which sell guns, require customers to pass background checks.

BANK OF AMERICA CORP

The bank said last year it would no longer lend to companies that make military-style firearms for civilians.

BLACKROCK INC

The world’s largest asset manager said last year it would offer investment strategies and exchange-traded funds that exclude civilian firearms producers and retailers. The company also said it was pressing gunmakers and weapons retailers in its portfolios to explain how they monitor firearm sales and use.

L.L. BEAN

The outdoor gear maker raised the minimum age for buying guns or ammunition at its stores to 21 in March 2018.

NATIONAL RIFLE ASSOCIATION-RELATED MOVES

DELTA AIR LINES, UNITED AIRLINES

The airlines said last year they were no longer offering NRA members discounted rates as the fallout from the 2018 massacre at a Florida high school took its toll on the gun advocacy group.

CHUBB LTD

The insurer said last year it would stop underwriting a NRA-branded insurance policy for gun owners that covers legal costs in self-defense shootings.

METLIFE INC

The insurer said it had ended an auto and home incentive program for NRA members in 2018.

SYMANTEC CORP

Last year, the cybersecurity company ended a discount program for its LifeLock identity theft product with NRA members.

HERTZ CORP

The company terminated discount programs on rental cars to NRA members in 2018.