They say that with great success comes great responsibility. Many of the world’s most iconic business leaders acknowledge this, and operate with an acute awareness of the legacies they will leave behind. Business moguls like Bill Gates, Warren Buffett, and Mark Zuckerberg are some of the better known philanthropists, donating their wealth, time and expertise to worthwhile causes close to their hearts.

But who are the dark horses? Who are the surprise philanthropists we don’t often hear about? In the spirit of giving this Holiday Season, we wanted to highlight some of the lesser known charitable figures in business. Don’t let the lavish lifestyles, outspoken personalities or capitalist sentiments fool you; these surprise philanthropists have big wallets, and even bigger hearts.

Elon Musk

Who? Sold Paypal to eBay for $1.5B in 2002, led series A financing for Tesla Motors, and founded SpaceX.

Surprise! He’s a father of 5, but admits he’s usually responding to emails when he’s with them, and employs a team of full-time nannies.

Philanthropy: He’s signed Warren Buffet’s Giving Pledge, an initiative for billionaires to give away much of their fortune after they die. He’s also given away millions to science education, pediatric health, and clean energy initiatives.

Paul Allen

Who? The lesser known co-founder of Microsoft

Surprise! Known for his lavish playboy lifestyle, owning a 414 ft mega yacht called Octopus, throwing wild parties, and investing in off-beat projects like a Frank Gehry-designed rock museum.

Philanthropy: He’s donated more than $1.5B to science, technology, education, wildlife conservation, the arts and community services. He’s also signed the Giving Pledge. In 2012, Allen was named the most charitable living American.

Sean Parker

Who? Co-founder of Napster and Facebook’s first President

Surprise! Famous for bringing music piracy to the masses, Sean Parker had an even bigger bad boy reputation following Justin Timberlake’s portrayal of him in The Social Network.

Philanthropy: Parker has directed around $20M in grants to support cancer immunotherapy research. He also founded Causes, a philanthropic service that uses social media to connect charities with supporters and potential donors.

Jack MacDonald

Who? After serving in the South Pacific during WWII, MacDonald became a lawyer and worked for Seattle’s Veterans Administration for 30 years.

Surprise! MacDonald lived a very humble life, clipping coupons and taking public transit to save most of his salary.

Philanthropy: After he passed away in September 2013, he left a staggering $187.6M to charity, including the Seattle Children’s Research Institute, University of Washington School of Law, and the Salvation Army. Despite donating 40 percent of his fortune to children’s research, MacDonald never had any children of his own.

JB Hi-Fi

Who? Ok, technically not a person, but this Australian home entertainment retailer deserves a shout out.

Surprise! In November 2008, JB Hi-Fi launched Helping Hands, a workplace program that allowed employees to donate to 9 charity partners through regular payroll deductions.

Philanthropy: Nearly 40 percent of employees participate in Helping Hands, donating part of their pay each week, with all donations being matched by JB Hi-Fi. In addition, senior managers donate at least 1 percent of their salary. Since the program began, JB Hi-Fi has raised $4.15M.

Talal Shakerchi

Who? CEO & Director of hedge fund Meditor Capital Management

Surprise! Shakerchi is also a professional poker player who has made over £1M in winnings.

Philanthropy: In the last two years, Meditor Capital has gifted £22.4M to a charitable trust administered by CAF. These efforts landed Shakerchi No. 4 on the Sunday Times Giving List in 2013. Based on his £100M net worth, Shakerchi has a “giving index” 22.4.

George Soros

Who? Business magnate, hedge fund manager, & investor

Surprise! Known as the “the man who broke the Bank of England,” Soros is famous for his investing prowess. He’s made most of his money betting on currencies.

Philanthropy: Between 1979 and 2011, Soros gave away over $8B to causes related to human rights, public health, and education. His organization, the Open Society Foundations, supports democracy and human rights in over 70 countries. Other notable projects have included aid to scientists and universities throughout Central and Eastern Europe.

Larry Ellison

Who? CEO of Oracle Corporation

Surprise! In 2012, Ellison was the highest paid CEO of a public company, earning $90.7M. He’s well-known for his lavish lifestyle, which includes yachts, luxury cars, and private jets.

Philanthropy: Ellison has donated over $800M to charity over the course of his life and was one of the original 40 billionaires to sign Warren Buffett’s Giving Pledge. Ellison plans to donate 95% of his wealth to charitable causes.

Marc Benioff

Who? Chairman and CEO of Salesforce

Surprise! Well-known for his outspoken personality, Benioff recently made headlines for mocking the plight of underpaid Walmart workers.

Philanthropy: When he founded Salesforce in 1999, Benioff implemented what is known as the “1/1/1” model. Using 1% of the company’s equity, 1% of the company’s profit in the form of product donations, and 1% of all employees’ time, Benioff established a nonprofit foundation, which he estimates has given away $40M in grants.