Corporate giants are making big contributions to disaster relief organizations to help victims of Tropical Storm Harvey.

The storm is expected to leave behind billions of dollars in damages.

Companies have pledged more than $157 million to relief efforts as of Saturday afternoon, according to an estimate from the U.S. Chamber of Commerce. Sixty-nine companies had donated $1 million or more so far.

Walmart has pledged up to $20 million in cash, products and matching donations, while Verizon has contributed $10 million. On Friday, tech billionaire Michael Dell pledged $36 million to relief efforts.

The figures are constantly changing as contributions continue to pour in -- and employee gift matching programs and customer donations are already bringing in even more funds.

"The corporate response thus far [has] been strong," Marc DeCourcey, senior vice president of the Chamber of Commerce Foundation, told CNNMoney.

Related: Impact Your World - How you can help

In 2005, Hurricane Katrina and Rita brought in more than $1 billion in business aid within the first six months of each disaster, according to the Chamber of Commerce Center for Corporate Citizenship.

The Indian Ocean tsunami in 2004 raised $566 million from corporate donations, while the 2011 Japanese earthquake and tsunami brought in $301 million. Hurricane Sandy in 2012 raised $141 million within the first six months in business aid, per the Chamber's data.

Companies have also gone beyond just writing a check, by volunteering, providing in-kind donations like water and food, and encouraging employees to donate by matching contributions, according to Mark Shamley, the president and CEO of the Association of Corporate Citizenship Professionals.

"The bottom line is companies have embraced their civic duty to respond to disasters in ways that transcend check writing," he said.

When companies respond to disasters, they build a tremendous amount of good will externally and internally, says Una Osili, associate dean at the Indiana University Lilly Family School of Philanthropy.

"Employees themselves want to work at companies that are engaged in a broader social good and making the community better," she said.

Many corporate giants are overwhelmingly donating to the Red Cross.

"We are extremely pleased and gratified by the outpouring of support we are receiving to help those affected," a Red Cross spokeswoman told CNNMoney.

Here's a running list of what foreign and domestic companies are doing to help.

Abbott: Abbott and its foundation the Abbott Fund are giving $1 million in grants and healthcare and nutrition products. That includes $900,000 in grants to the Red Cross, Americares and Direct Relief, and $100,000 in healthcare and nutrition products.

Abbvie: The AbbVie Foundation is giving $1 million in grant funding for organizations like Red Cross, AmeriCares, Direct Relief International, and Feeding America. It is also matching employee donations made to relief organization.

AdvoCare: The nutrition and wellness company pledged $50,000 and another $50,000 in matching funds for donations gathered on the American Red Cross portal on its site.

Aetna: The Aetna Foundation announced a $100,000 contribution to both the American Red Cross and the Community Foundation of Greater Houston. It will also donate $50,000 to nonprofit Team Rubicon to assist current and future disaster relief efforts.

Air Products: The Air Products Foundation is contributing $100,000 to the Red Cross and local agencies in the Gulf Coast. It is also matching employee donations.

Albertsons: The food and drug retailer is matching the first $200,000 donated by its customers in stores and online.

Allergan: The Allergan Foundation on Monday said it will donate $100,000 to the Red Cross to support victims of Harvey.

Allstate: Allstate and the Allstate Foundation have pledged $1.5 million to Harvey relief. The company is also matching employee and agency owner contributions.

Amazon: Amazon and Whole Foods matched $1 mllion in cash donations made on Amazon.com to the Red Cross Hurricane Harvey Relief.

Ameren: The power company is giving $25,000 to the Red Cross.

American Express: American Express is donating $150,000 to the Red Cross. It will match up to $100,000 in employee donations to the Red Cross.

Amgen: Amgen, a biopharmaceutical company, is donating $80,000 to Direct Relief International and $20,000 to the American Kidney Fund's Disaster Relief Program to help dialysis patients impacted by the storm. The company will also match employee donations.

Anadarko: The company donated $1 million to Greater United Way Disaster Relief Fund.

Andersen: The manufacturer of windows and doors is making a $50,000 donation to the Red Cross. It will also match up to $25,000 in employee contributions. The company is also giving $100,000 worth of windows and doors to Houston Habitat for Humanity to help with rebuilding efforts.

Apple: The tech giant made a $2 million donation to the Red Cross over the weekend, an Apple spokeswoman told CNNMoney. Apple will also match employee donations 2 to 1. Users can donate to the Red Cross through iTunes or on the App Store. The company has helped raise more than $1 million over the past few days, according to an employee email obtained by CNN.

AT&T: AT&T is contributing $350,000 to help communities following the storm, including $100,000 to the Greater Houston Community Fund, $100,000 to the Red Cross Hurricane Harvey Fund and $50,000 to the Coastal Bend Community Foundation in South Texas.

The AT&T Foundation will match employee donations up to $50,000 each to Team Rubicon and to the AT&T Employee Disaster Relief Fund, which supports employees who live in the areas affected by the storm. (AT&T is acquiring Time Warner, the parent company of CNN.)

Associa: The homeowner and property management company pledged $50,000 to the Red Cross through its non-profit Associa Cares.

Avangrid: The energy and utility company will contribute $50,000 to Red Cross Disaster Relief through its foundation.

Bank of America: The Bank of America Charitable Foundation is donating $1 million to support Harvey relief efforts, including a $250,000 donation to the Red Cross. The remainder of the funds will be allocated as the company learns more about recovery needs, a spokesperson told CNNMoney.

Bank of America will also match employee donations of $1 or more until September 30. Its usual gift match minimum is $25.

Bass Pro Shops: The sporting good store has pledged $40,000 worth of supplies to relief efforts.

Bayer: Bayer told CNNMoney it is donating $100,000 each to the Red Cross and nonprofit Direct Relief.

BB&T: Bank BB&T is giving $100,000 to the Red Cross of Greater Houston in Texas.

BBVA Compass: BBVA Compass' foundation will contribute $250,000 to the Red Cross and the Hurricane Harvey Relief Fund. The bank also aims to raise up to $250,000, both online and at its branches, from employees and customers for those organizations.

Boehringer Ingelheim: The Boehringer Ingelheim Cares Foundation is contributing over $100,000 to Americares and Direct Relief International. It is also donating $25,000 to the Texas A&M Foundation to help animals impacted by Harvey.

Boeing: The Boeing Charitable Trust committed $1 million to the Red Cross for Harvey relief efforts.

BMO Financial: Financial services provider BMO Financial contributed $100,000 to the Red Cross.

BP: BP and the BP Foundation have donated $750,000 to assist with relief efforts. The contribution will be split equally among the Red Cross, the Community Foundation of Greater Houston and the United Way of Greater Houston. The company will also match employee contributions.

Bristol-Myers Squibb: The pharmaceutical company and its foundation are donating $250,000 to Americares, Direct Relief International and the Red Cross. Its foundation will also match employee donations to organizations working on relief efforts. It is also giving medicines valued at $10 million to Americares and Direct Relief.

Campbell Soup: The company made a $50,000 contribution to the Red Cross and United Way of Greater Houston. It will also match employee donations to the Red Cross up to $25,000. The company is also donating food products.

Camping World: The retailer will match customer donations up to $2 million made in stores to the Red Cross. The company is also accepting clothing and apparel donations.

Cargill: The company made a contribution of $150,000 to the Red Cross and Feeding America. It is also matching employee donations.

CarMax: CarMax and its foundation are pledging $100,000 to the Red Cross. For every dollar an employee donates to the Red Cross, the foundation will double the amount. It is also providing impacted employees with up to $1,500 through CarMax's Associate Disaster Relief Fund.

Carnival Cruise Line: The cruise line and its philanthropic arm Carnival Foundation are donating $1 million to disaster relief efforts. Carnival Chairman Micky Arison and his wife Madeleine are also contributing $1 million from their foundation.

Caterpillar: The Caterpillar Foundation donated $300,000 to the Red Cross to help with immediate relief efforts for Harvey.

Cheniere Energy: Cheniere Energy on Monday said it will make a $1 million donation to the Red Cross to help with relief and recovery efforts following the storm.

Chevron: Chevron is making a $1 million donation to the Red Cross. The oil and gas company will also match donations made to relief efforts by its employees and retirees.

Cigna: The Cigna Foundation is contributing $100,000 to the Red Cross. Cigna employees can also request matching funds for their donations to the Red Cross.

Citgo: The petroleum company is giving $3 million to relief efforts in Houston. The company said that contribution came out of a $5 million fund the company has pooled together to help provide aid primarily to Corpus Christi, Houston and Lake Charles, Louisiana -- all of which are home to Citgo facilities.

Citi: The Citi Foundation has committed a $1 million donation to the Red Cross, the company told CNNMoney.

Coach: The Coach Foundation has committed $200,000 to the Red Cross. Coach (COH) will also match employee contributions.

Coca-Cola: The Coca-Cola Foundation pledged $1 million to the Red Cross on Tuesday. Coca-Cola (KO) will also match employee donations made to the company's Employee Disaster Relief Fund up to $100,000.

Comcast: Comcast NBCUniversal is giving $500,000 toward the Houston Mayors' Hurricane Harvey Relief Fund and the Red Cross. The organizations will share the donation. The company will also donate advertising time on its cable networks to these organizations to run public service announcements about how to aid with flood relief efforts.

Comerica: The Dallas-based bank will donate $100,000 to the Red Cross.

ConocoPhillips: The company is making a $2.5 million donation to both the Red Cross and the United Way of Greater Houston.

Employees and retirees in the U.S. can request to have their personal contributions matched.

CVS: CVS Health and the CVS Health Foundation announced $200,000 in cash and in-kind product donations, including $50,000 each to the Greater Houston Community Foundation and the Red Cross, and $25,000 to the Salvation Army. CVS will also match employee contributions up to $25,000.

Del Frisco's Restaurant Group: The company is donating 20% of sales from Thursday to Monday across all 53 restaurants. Its goal is to donate $1 million to Houston area food banks.

Dell: Dell has pledged $500,000 the American Red Cross and Team Rubicon. The company will also match employee contributions up to $10,000 per person each year.

Direct Energy: The company is matching donations up to $25,000 to the Red Cross on this website.

Discover: Discover will match donations up to $500,000 for every cardholder who donates to the Red Cross via their Cashback Bonus program or makes a donation with a Discover card. The company is also matching employee donations.

Disney: Disney and ABC's Houston TV station KTRK-TV announced a $1 million contribution to the Red Cross. The company is matching employee donations.

Dollar General: Dollar General is donating $50,000 to the Red Cross. Customers can also make a contribution in stores through September 9.

Dow: The Dow Chemical Company Foundation is contributing $1 million to support Harvey relief, including $100,000 each to the Red Cross Disaster Relief Fund and Team Rubicon. Dow is also matching employee and retiree donations up to $100,000 to the Red Cross.

Edmunds: The company is pledging $50,000 toward local relief efforts. Edmunds is also matching employee donations up to $500 per person.

Eli Lilly: The pharmaceutical company's foundation is contributing $250,000 to the Red Cross. It will also match employee donations to the Red Cross and Salvation Army.

Enterprise Rent-A-Car: The Enterprise Rent-A-Car Foundation is donating $1 million to the Red Cross.

Exelon: The utility company is donating $150,000 to the Red Cross. Exelon will also match employee contributions up to $5,000 per person.

Exxon Mobil: Exxon Mobil on Friday said it's donating $500,000 to Red Cross organizations along the U.S. Gulf Coast to aid with relief efforts. On Tuesday, the company contributed $500,000 to the United Way of Greater Houston.

Exxon will also match employee donations up to $3 million.

Facebook: Facebook donated $1 million to organizations on the ground providing support. The social media giant on Thursday said more than $10 million has been raised on its platform for Harvey relief.

FedEx: FedEx committed $1 million in cash and transportation support to deliver medical aid and supplies in the wake of the storm. It works with the Red Cross, Direct Relief, Heart to Heart International, the Salvation Army and Team Rubicon.

FirstEnergy: The company's foundation will donate $25,000 to the Red Cross and match employee contributions up to $50,000.

Ford: The Ford Motor Company Fund is donating $100,000 to disaster relief efforts. Texas-area Ford dealers have also donated $200,000. The automaker has also promised to raise a total of $3.5 million by matching donations to designated community relief charities.

General Electric: The GE Foundation has donated $500,000 to the Red Cross, a spokeswoman told CNNMoney. It will also match employee donations to participating disaster relief organizations.

General Mills: The company is sending more than $500,000 in food donations, such as Yoplait and Nature Valley products, to help those displaced by the storm. It will match employee gifts up to $250 per person.

Google: The tech giant is making a $250,000 Google.org grant to the Red Cross and matching employee donations up to $250,000. Google.org also launched a matching campaign for consumers, up to $1 million.

H-E-B Grocery: H‑E‑B Grocery will donate $100,000 toward Hurricane Harvey relief efforts, specifically to the Red Cross, Salvation Army and Feeding Texas. Customers can also make a donation at its Texas stores.

HCA Healthcare: HCA donated $1 million to the American Red Cross.

Hilton: The company is donating $500,000 to the Red Cross and to the Hilton Responds Fund for affected employees. The Conrad N. Hilton Foundation, a private family foundation established by the founder of Hilton Hotels, has also pledged $500,000.

Home Depot: The home improvement retailer on Monday committed $1 million to help storm relief efforts. The donation will go to nonprofits, such as the Red Cross, Salvation Army, Convoy of Hope, Operation Blessing and Team Rubicon.

Honda: The company has pledged $100,000 to the Red Cross.

Humana: The Humana Foundation, the philanthropic arm of health insurance company Humana, (HUM) on Saturday gave a $250,000 immediate grant to the Red Cross.

IBM: IBM is donating $2 million in cash and in-kind technology and services. The company said it will support the Red Cross and small businesses.

Intercontinental Exchange: ICE is making a $1 million contribution to the Red Cross and matching employee donations.

International Paper: The company has pledged $1 million to help with disaster relief efforts, including $750,000 to Red Cross chapters in Texas and Louisiana and $250,000 to Feeding America.

J.C. Penney: The department store is donating $100,000 to the Red Cross.

Jefferies: Investment bank Jefferies announced a $1 million donation to several charities aiding in the relief effort. On Thursday, the firm said its clients, employees and shareholders contributed $5 million to 14 organizations.

JPMorgan Chase: The firm said it would donate $1 million to the Red Cross and other nonprofit groups providing immediate relief. JPMorgan is also matching employee donations to these organizations.

Chase will also automatically waive or refund fees, such as late fees for mortgages and credit cards, through September 10 for customers in areas severely impacted by the hurricane.

Kansas City Southern: Its charitable fund will donate $50,000 to the Red Cross. The railroad company will also match employee gifts up to $25,000.

Kellogg: Kellogg Company Fund, the charitable arm of Kellogg, is committing $100,000 to nonprofit Feeding America to aid disaster relief efforts.

Kindred Healthcare: Kindred Healthcare is making a $50,000 donation to the Red Cross to aid recovery efforts from Harvey in Texas and the Gulf Coast.

Kohl's: Kohl's announced a $500,000 donation to the Red Cross. The department store will also give an estimated $1 million to help Kohl's associates who were significantly affected by the storm.

Kroger: The Kroger Co. Foundation committed $100,000 to the Houston Food Bank. For every share of Kroger's Facebook post, the foundation will donate $5 to the Food Bank, up to $100,000.

Lennar: The homebuilder donated $1 million to the United Way of Greater Houston Flood Relief Fund. The company will also match employee contributions.

Lowe's: The home improvement retailer on Saturday announced a $500,000 contribution to American Red Cross Disaster Relief to help provide food, shelter and supplies to those impacted by Harvey and other crises. At Lowe's stores in Texas, customers can also make a donation to the Red Cross.

LyondellBasell: The chemical company donated $200,000 to the American Red Cross Texas Gulf Coast Region.

Macy's: The department store gave $50,000 to the Red Cross and is matching employee donations and customer contributions in stores. Macy's also donated $1 million to the United Way's Hurricane Harvey relief fund.

MasterCard: The company donated $100,000 to the Red Cross. Mastercard will also match employee donations.

Mattress Firm: The Houston-based mattress retailer started an employee assistance fund and contributed the first $25,000. Mattress Firm will also match employee donations up to $100,000. The company is also giving $1 million in products.

Mazda: Mazda and its foundation will donate $100,000 to the Red Cross Hurricane Harvey Disaster Relief Fund.

McDonald's: The fast-food giant will contribute $1 million to the Red Cross. It will also match $250,000 in employee donations.

McKesson: The pharmaceutical distributor is donating $100,000 to nonprofit Direct Relief and $150,000 worth of medical supplies to World Vision.

MetLife: The MetLife Foundation will donate $250,000 to the Red Cross and match employee contributions.

Microsoft: Microsoft on Monday announced a $100,000 grant to the Red Cross. The tech giant is also contributing another $2.5 million in cash, technology and services to support relief efforts and to aid nonprofit and public-sector organizations.

MillerCoors: MillerCoors is pledging at least $25,000 to the Red Cross. The company also sent 50,000 cans of drinking water to Texas, where they will be distributed by the Red Cross.

Monsanto: The company will donate $500,000 to the Red Cross and Feeding America.

Motiva: The Houston-based oil company pledged $500,000 to organizations such as the Houston mayor's Hurricane Harvey Disaster Relief Fund and the Red Cross.

Nationwide: The Nationwide Foundation is giving $500,000 to Red Cross Disaster Relief.

New York Life: New York Life is donating $500,000 to support Harvey relief efforts, including $150,000 to the Red Cross and $100,000 apiece to Save the Children and Feeding Texas. The life insurance company will also match employee donations up to $150,000 to these organizations.

NextEra Energy: The company is contributing $100,000 to the Red Cross and will match employee donations up to $100,000.

NRG Energy: The Houston-based company is donating $1 million to organizations including the Greater Houston Community Foundation, the Red Cross and the J.J. Watt Foundation Houston Flood Relief Fund. NRG also says its providing another $1 million in community support and customer assistance.

NuStar Energy: NuStar Energy is giving $125,000 to Red Cross, $75,000 to Salvation Army and $50,000 to the San Antonio Food Bank. The Greehey Family Foundation, which was started by NuStar Chairman Bill Greehey, is also giving the same amount to each group.

Oncor: The Dallas-based utilities company has contributed $100,000 to the Red Cross.

Orbital ATK: The aerospace and defense company is giving $100,000 to the United Way of Greater Houston.

Pacific Life: Its foundation donated $100,000 to the Red Cross. The life insurance company is also matching employee donations.

Panda Express: The company's foundation Panda Cares will donate $500,000, divided between the American Red Cross and the Tzu-Chi Foundation. Customers can also make a contribution in stores through September 15.

PayPal: The payments platform will match employee donations. PayPal also launched a Disaster Relief Campaign.

PenFed Credit Union: PenFed, one of the country's largest credit unions, will donate $50,000 to the Red Cross Corpus Christi and Houston chapters.

Pentair: The Pentair Foundation made a $25,000 donation to the Red Cross. The manufacturing company will also match employee contributions.

PepsiCo: PepsiCo and the PepsiCo Foundation gave a $1 million grant to the Red Cross.

PetSmart: PetSmart Charities is giving $1 million to help animal welfare agencies that are working to rescue, relocate and care for pets that have become homeless due to the storm. These organizations include the Houston SPCA, the SPCA of Texas, Rescue Bank and Houston PetSet. The company is also providing in-kind donations, like pet food and supplies.

PG&E: Pacific Gas and Electric Company (PG&E) will match employee donations up to $50,000.

Phillips 66: Phillips 66 will contribute $1 million to the Red Cross. The oil company will also match employee contributions up to $15,000 per person.

Pioneer Natural Resources: The company contributed $100,000 to the Red Cross and will match employee donations.

PNC: The PNC Foundation, the philanthropic arm of PNC bank, will contribute $250,000 to the Red Cross and match employee donations up to $100,000.

QVC: QVC is making a $100,000 donation to the Red Cross and will match employee contributions up to $50,000. It will also match customer donations to the Red Cross up to $100,000.

Range Resources: The oil and gas company announced a $100,000 donation to the Red Cross for Harvey relief aid.

RBC: The bank is donating $100,000 to the Red Cross.

Regions Bank: The bank is donating $100,000 to support relief efforts. The funds will be split between the United Way of Greater Houston's Flood Relief Fund and a program to help Regions associates directly impacted by the flooding.

Reynolds American: The Reynolds American Foundation contributed $150,000 to the Red Cross.

Rockwell Collins: The company has pledged $100,000 to the Red Cross.

Ross Stores: Ross Stores made a $400,000 donation to the Red Cross. The discount retailer is also accepting customer contributions in stores until September 16.

SABIC: The Saudi chemical manufacturing company donated $200,000 to the Red Cross Texas Gulf Coast Region.

Samsung: Several of Samsung's U.S. subsidiaries are donating $500,000 to the Red Cross. The company is also giving $500,000 worth of products, such as washing machines, dryers, laptops and tablets, to nonprofits.

Schweitzer Engineering Laboratories: SEL has contributed $150,000 to the Red Cross for relief efforts.

Sealed Air: Sealed Air is making a $100,000 donation to the Red Cross. The company will also match employee contributions up to $25,000.

SecureView: The company contributed $100,000 to the Red Cross.

Sempra Energy: The Sempra Energy Foundation will contribute $75,000 each to the Red Cross Hurricane Harvey Relief Fund and nonprofit Americares. The foundation will also match up to $50,000 in employee donations.

Shell: Shell announced a $1 million donation to the Red Cross Hurricane Harvey disaster relief fund on Tuesday.

Southern Company: The Southern Company Charitable Foundation will give $100,000 to the Red Cross. The company will also match employee and retiree donations.

Southwest Airlines: The airline donated $500,000 to the Red Cross.

Sprint: Sprint and SoftBank are donating $2.5 million in cash to support the Red Cross, Sprint employees affected by Harvey and other community relief efforts.

Stanley Black & Decker: Stanley Black & Decker announced a commitment of up to $125,000 for immediate disaster relief, including a $50,000 donation to the Red Cross and $25,000 to the Houston ToolBank. It will also match employee donations 2 to 1.

Starbucks: The Starbucks Foundation donated $250,000 to the Red Cross. Customers can also make a contribution to Harvey relief efforts at any Starbucks (SBUX) store in the U.S.

State Farm: State Farm is matching employee donations through its Matching Gift Program. Its foundation matches employee donations to nonprofits from a minimum of $25 to a maximum of $1,500 per calendar year.

Stream Energy: The Dallas-based home energy and wireless provider, donated $25,000 through its philanthropic arm Stream Cares to the Red Cross Disaster Relief Fund.

SunTrust: The SunTrust Foundation (STI) announced a $100,000 grant to the Red Cross.

Sysco: The Houston-based food distributor said it will donate $1 million to relief efforts, including an "immediate" contribution of $500,000 to the American Red Cross.

Target: The retailer is donating $500,000 to support Harvey recovery efforts, including to organizations like the Red Cross, Salvation Army and Team Rubicon.

Taylor Morrison: The homebuilder has donated a combined $250,000 to the Red Cross Harvey Fund and to an internal Harvey relief fund. It will also match employee contributions.

TD Ameritrade: The company will match employee and client donations up to $500,000 to the Red Cross.

TechnipFMC: The oil and gas projects company is donating $1 million to the United Way of Greater Houston.

Tegna: The broadcasting company launched Texas Cares, an initiative to support Harvey victims for employees and customers. The fund has raised over $1.5 million as of Wednesday morning. Tegna matched the first $100,000 in donations. All of the funds raised will be donated to the Red Cross Hurricane Harvey Relief Fund.

Tenet Healthcare: Tenet Healthcare Foundation contributed $20,000 to the Red Cross.

Texas Instruments: TI is making a $100,000 donation to the Red Cross. The company is also matching the donations of employees and retirees up to $100,000.

Time Warner: Time Warner, the parent company of CNN, will make a $100,000 donation to Houston Habitat for Humanity, the Houston Humane Society, Save the Children and Shelterbox. Employees can also have their donation matched through the Matching Grants Program.

Toyota: Toyota is pledging $3 million to Harvey relief, including cash contributions to the St. Bernard Project and American Red Cross, matching employee and dealer contributions and donating pre-owned vehicles. Dan Friedkin, the chairman of Houston-based Gulf States Toyota, has also established the Friedkin Disaster Relief Fund and pledged $1 million.

TransCanada: The energy infrastructure company made a $100,000 contribution to the Red Cross and is matching donations online.

TXU Energy: The company is giving $500,000 to assist customers who need help paying their electric bills in areas affected by Harvey.

Under Armour: Under Armour donated $50,000 to assist Team Rubicon in response to Harvey.

Union Pacific: Union Pacific has pledged $250,000 to support Hurricane Harvey relief efforts, including $100,000 to the Red Cross and $50,000 to Houston Mayor Sylvester Turner's Hurricane Harvey Relief Fund. The railroad company will match contributions to its employee support network through September 30, up to $100,000. It will also match donations made to the Disaster Relief Matching Gifts Program for Hurricane Harvey, where employees can contribute funding to the Red Cross, Salvation Army and other groups.

UnitedHealth: UnitedHealth announced a donation of $1 million to support Texas communities impacted by the storm. The company said it's working with officials and stakeholders in Texas to determine "how the funds can most effectively support relief efforts." It is also offering a 2 to 1 match for employee donations toward disaster relief efforts.

United Airlines: The airline will give up to three million bonus miles to MileagePlus members who donate to disaster relief organizations such as the Red Cross or AmeriCares. United (UAL) will also match the first $200,000 raised in donations on its crowdfunding campaign.

United Rentals: The equipment rental company is pledging $200,000 to the Red Cross.

UPS: The UPS Foundation has pledged $1 million to Harvey relief efforts. This includes a combination of cash grants, in-kind transportation donations and technical expertise.

UPS will donate an additional $500,000 in cash and assistance for the post-crisis recovery phase in the coming months.

Valero: The oil company announced a $1 million donation to the Red Cross.

Verizon: Verizon pledged $10 million to support Harvey relief efforts. The grants will go to organizations like the Greater Houston Community Foundation, the One Star Foundation and the Salvation Army Southern Territory.

Visa: Visa will make a $250,000 donation to the Red Cross and match employee donations two to one.

Vizient: The Dallas-based company is giving $1 million in funds and employee match contributions.

Walgreens: Walgreens pledged $200,000 to the Red Cross. Customers can also make a donation in stores in the U.S., Puerto Rico and U.S. Virgin Islands.

Walmart: Houston Mayor Sylvester Turner said he was accepting $2 million from Walmart and the Walmart Foundation. The retail giant is also matching customer donations two to one with cash and products of up to $10 million to support the Red Cross. Walmart and its foundation will also give cash and products totaling $10 million to organizations like the Salvation Army, Feeding America, Convoy of Hope and Team Rubicon.

Waste Management: Waste Management announced a $3 million donation to various organizations, including the Houston Mayor's Fund and the Red Cross.

Wells Fargo: Wells Fargo is donating $500,000 to both the Red Cross Disaster Relief Fund and to local nonprofits focused on relief efforts in Texas.

Western Union: The money transfer company's foundation announced a $30,000 donation to the Red Cross on Sunday. The Western Union Foundation will also match contributions from its agents, and the first $100,000 from Hurricane Harvey Telethon contributors in Denver.

Whataburger: Texas burger-chain Whataburger said it is donating $150,000 to the Red Cross and $500,000 to local food banks. The company said it is also donating $1 million to the Whataburger Familiy Foundation, which it says "provides emergency assistance to Whataburger Family Members who are experiencing an unforeseen financial hardship." It will also provide free money transfers when users send funds to Texas from the U.S.