The National Rifle Association lashed out at corporations rushing to abandon it on Saturday, as companies from United Airlines to Best Western have cut ties with the gun lobby group under pressure from a boycott movement following a Feb. 14 high school shooting.

Without context, twin announcements from Delta and United airlines on Saturday morning might look trivial: The end of flight discounts to the NRA’s annual convention, which few outside the gun rights organization likely knew existed before they became boycott targets.

“Delta is reaching out to the NRA to let them know we will be ending their contract for discounted rates through our group travel program. We will be requesting that the NRA remove our information from their website,” the airline announced on Twitter.

“United is notifying the NRA that we will no longer offer a discounted rate to their annual meeting and we are asking that the NRA remove our information from their website,” United said on Twitter.

But in abandoning the NRA, the airlines followed car rental giants Avis, Hertz and Enterprise, the Best Western hotel chain, the global insurance company MetLife, and more than a dozen other corporations that have severed affiliations with the gun group in the last two days.

In a statement released Saturday afternoon, the group accused companies of “a shameful display of political and civic cowardice.”

“Let it be absolutely clear. The loss of a discount will neither scare nor distract one single NRA member from our mission to stand and defend the individual freedoms that have always made America the greatest nation in the world.”

While it’s unclear what effect the corporate snubs will have on the NRA, they have given the nascent #BoycottNRA a string of rapid, prominent victories and exposed vulnerabilities in a gun rights lobby that had seemed untouchable before 17 students are Marjory Stoneman Douglas High School in Parkland, Florida, were gunned down last week.

The NRA claims 5 million members and takes in tens of millions of dollars each year through supporters, which it uses to fight gun regulations in the name of the U.S. Constitution, which guarantees Americans the right to bear arms.

The group has faced public anger before – after the massacre of schoolchildren at Sandy Hook Elementary in 2012, for example. But it has always fought back against pushes for new gun laws, and efforts to significantly restrict firearms inevitably die out as public fury over the shootings ebbs.

But outrage over the Parkland shooting – sustained in part by politically active teenagers who survived the massacre – has shown no signs of fading. Police say a former student killed 17 people with a legally purchased semiautomatic rifle, one of at least 10 guns he owned.

As calls for gun control have spread, the NRA has increasingly become a target of activists, with social media hashtags urging boycotts of any corporation found to be linked with it.

Delta and United are the latest to submit to the pressure.

First National Bank of Omaha, one of the largest private U.S. banks, may have been the first to respond publicly to the boycott calls. The bank had previously advertised the “Official Credit Card of the NRA,” according to the Omaha World-Herald – a Visa card with 5 percent back on gas and sporting good purchases.

“Customer feedback has caused us to review our relationship with the NRA,” the bank said in a statement published Thursday, eights days after the Parkland shooting. “As a result, First National Bank of Omaha will not renew its contract with the National Rifle Association to issue the NRA Visa Card.”

Enterprise followed suit a few hours later. “All three of our brands have ended the discount for NRA members,” effective March 26, the car rental company wrote on Twitter Thursday afternoon. Hertz, Avis Budget Group and TrueCar would soon join Enterprise and end their NRA discounts. So did movers North American Van Lines and Allied Van Lines.

On Friday morning, Symantec announced that the boycott movement had spread to the software industry. NRA members will now have to pay the same price for its anti-virus software as everyone else.

On the same day, insurer Chubb Limited announced that it will stop underwriting “NRA Carry Guard,” a policy marketed to NRA members who face legal or civil lawsuits after they shoot someone, which gun opponents sometimes call “murder insurance.” A spokesman for Chubb told Reuters that the company had made the decision months ago, but its announcement of the fact on Friday only increased the perception of a boycott movement swelling against the NRA.

It has now spread across numerous industries and affected some of the world’s largest corporations. The global insurance company MetLife said it has terminated discounts for NRA members. Best Western and Wyndham Hotels announced they are no longer affiliated with the NRA.

Facing questions from the liberal outlet ThinkProgress about its discounts for NRA members flying to the group’s convention in May, a Delta spokesman at first defended the program as “routine.” The airline “has more than 2,000 such contracts in place,” the spokesman said, ThinkProgress wrote Friday evening.

Come daybreak, Delta abruptly discontinued the discounts and asked the NRA to take the airline’s name off its website. United Airlines followed suit the same morning.

Like other companies that ditched the NRA, the airlines faced an immediate backlash from gun rights supporters.

Some other companies have, so far, not been moved by the boycott calls. FedEx, for example, still gives NRA Business Alliance members up to a 26 percent discount on shipping expenses. Google, Amazon, Apple, AT&T and Roku all stream an NRA-produced video channel despite pressure from gun-control groups.

This follows a week when NRA leaders spoke defiantly at public appearances, blaming the fury on media manipulation.

“Many in legacy media love mass shootings,” Loesch said Thursday at a conservative political conference. “Crying white mothers are ratings gold.”

“They want to make us all less free,” NRA chief executive Wayne LaPierre said when he took the microphone. The correct response to the Florida shooting, he said, was more armed security on school campuses – not fewer guns in the United States.

Pressure campaigns have become a favorite tool of liberal groups during Trump’s presidency – from early efforts to boycott Trump-branded products to a Twitter campaign that identified and exposed people seen marching at a far-right protest in Charlottesville this past summer. Social media and Internet companies began to ban far-right personalities from their sites after that rally turned violent.

So far, for all the companies that have signed on, the NRA boycotts have managed only to wipe out a few peripheral perks for the group’s members. But if the movement keeps spreading, there are signs it could threaten the financial and political cornerstones of the gun lobby. Still, the long-term effects are unknown.

After the Parkland shooting, a prominent City Council member in Dallas said the city no longer wants the NRA to hold its convention there in May, Fox News reported. But officials in Kansas and Nebraska have invited the gun group’s business.

Florida Gov. Rick Scott and other Republicans have endorsed banning rifle sales to anyone under age 21 – which the NRA opposes. Sen. Marco Rubio, R-Fla., on the other hand, at a recent CNN town hall this week said he would continue to accept political contributions from the gun rights group.

According to Business Insider, the NRA is funded largely by the gun industry, which has contributed tens of millions of dollars and helped the gun lobby build alliances and power networks across the U.S. political system.

The same industry, of course, also makes many off the hundreds of millions of guns believed to be in the country. So the most ambitious gun-control advocates would love to cut off that financial backing.

The Parkland shooting and its negative publicity caused the investment giant BlackRock to explore ways of letting its clients disinvest from gun companies, Bloomberg News reported. Teachers in Florida are pressuring their pension fund managers to do the same. But gun industry stocks are widely held. CNBC reported this week that some of Wall Street’s largest exchange-traded funds include holdings in several gunmakers.

And investors may be hesitant to dump gunmakers’ stocks as long as the companies remain lucrative.

New York Times financial columnist Andrew Ross Sorkin, five days after the Parkland shooting, made a proposal: Banks and credit companies could effectively ban assault weapons right now, simply by prohibiting customers from using their services to buy them.

Financial companies ban the purchase of products like cryptocurrency with credit cards, Sorkin wrote, and some executives were considering policies that would lead “assault weapons [to] be eliminated from virtually every firearms store in America because otherwise the sellers would be cut off from the credit card systems.”

Gunmakers, of course, also use credit to make purchases, so banks could throttle them from the supply side, as well. Whether banks would do this, however, is in question. In 2012, Snopes investigated a report that Bank of America was cutting off credit lines to gun manufacturers. A spokeswoman for the bank denied the report, saying it had no policies against doing business with the firearms industry and pointing to a $250 million deal with a gunmaker that same month.

Six years later, amid the growing outrage from the Stoneman Douglas massacre, the bank sounds very different.

Axios reported on Saturday that Bank of America was “reexamining” its relationship with AR-15 rifle manufacturers who do business with it.

“We are joining other companies in our industry to examine what we can do to help end the tragedy of mass shootings,” Bank of America said in a statement.

The Washington Post’s Fred Barbash, Lindsey Bever, T.J. Ortenzi, Keith McMillan, Desikan Thirunarayanapuram and Steven Zeitchik contributed to this report.