Mangosteen

One outsourced solution for all your business operations

Startups are our passion.
Your success is our mission.

We are a team of professionals with a passion for supporting exciting new ventures.

  • Integrity
  • Transparency
  • Persistence
  • Kindness
  • Curiosity
  • Ingenuity

Decades of combined experience, perfected time and time again.

We are a team of client service professionals specializing in all practice areas of your back office. What is perceived as non-core operations of a business is what we’ve perfected time and time again over decades of combined experience.

We provide entrepreneurs, startups and investment platforms with a comprehensive solution that integrates all back office operations under a single platform, that is customizable to the specific needs of the business, and that benefits the entire organization.

We help you manage your operations effectively and efficiently, which increases your productivity and allows you to focus more on growing the business.

The values we work by.

Integrity

The practice of being honest, truthful, showing a consistent and uncompromising adherence to strong moral and ethical principles and values.

Transparency

Operating in such a way that it is easy for others to see what actions are performed; it implies openness, communication, and accountability.

Persistence

Firm or obstinate continuance in a course of action in spite of difficulty or opposition.

Kindness

Behavior marked by ethical characteristics, a pleasant disposition, and concern and consideration for others.

Curiosity

Quality related to inquisitive thinking, from which derives the process of learning and the desire to acquire knowledge and skill.

Ingenuity

The quality of being clever, original, and inventive, often in the process of applying ideas to solve problems or meet challenges.

About our founder

Sam Milenkov, Founder and CEO of Mangosteen Solutions
Sam Milenkov

Founder & CEO

Company and management profiles are often written in the third person, which I’ve always found a bit impersonal and awkward. Since I place a high value on human relationships, both professionally and personally, and strongly believe in radical transparency and authenticity, here’s a first-person reflection on who I am.

After spending over 15 years in and around startups, I set out to build a professional services organization with a clear mission: to support early-stage ventures with their back-office operations.

My professional journey began with a rewarding career in the consumer and industrial markets practice at one of the Big Four audit firms, covering anything from small startups to large public multinationals. At KPMG, I had my first exposure to high-growth companies and early-stage ventures.

That experience opened the door to an opportunity at Allied Minds, an investment platform that launched and operated companies out of U.S. universities and federal labs. It was there that I truly discovered my passion for the venture creation process. After several years on the investment side, starting as the first finance hire and eventually leading finance through the Allied Minds IPO on the London Stock Exchange, I decided to experience the startup world from the inside. I transitioned into the colloquial “serial startup CFO” track for a number of startups.

Along the way, through my roles in audit, investment, and as a hands-on executive, I remained industry-agnostic. The one consistent theme? Working with tough, deeply disruptive technologies, often at the peak of their innovation cycles. From cancer therapeutics to lower Earth orbit satellites, micro-mobility when scooters were being tossed into rivers in 2021, cell and gene engineering during the COVID pandemic, blockchain technology during the FTX and banking crisis of 2022, and recently generative AI and deep tech innovation, I’ve always gravitated toward ventures tackling the hardest problems of the day. As I like to say, accounting can only be so exciting; the real thrill comes from aligning with a company’s mission and purpose.

In the dynamic, all-hands-on-deck environment of startups, I came to realize that being a strong CFO isn’t just about being proficient in accounting & finance. The CFO and COO roles often converge, and a truly impactful CFO must also be a capable operator and strategist.

This belief is reflected in my deep commitment to the entire venture-building process, and it’s what drives my mission: to help young entrepreneurs launch and manage their operations as they pursue bold ideas that make the world a better place.

I maintain a relentless focus on quality of work and meaningful personal relationships. I’m passionate about leveraging technology that enhances rather than replaces the human experience. I credit my inherent resilience, drive for survival and success, and empathy for the heartache that every entrepreneur faces, to my immigrant background.

On a more personal note, I’m unapologetically obsessed with being a dad. Watching my kids grow and discover the world fascinates me. It would be cliché to list all the things we do together as a family; what truly matters is simply being together and sharing life through its highs and lows. Recently, I’ve developed a deep appreciation for my own health, fitness, and longevity (so I can enjoy more of the above, longer), and I’ve grown especially fond of triathlon, as both a sport and a mindset.

The Milenkov family at the Isabella Stewart Gardner Museum, Boston
Left to right: Alen, Rosi, Mia, Sam at the Isabella Stewart Gardner Museum, Boston (2025)

What is Mangosteen?

The source of our inspiration.

We are purposeful in every way. Nothing that we do is accidental.

Illustration of a mangosteen fruit, whole and cut open to show its segments

On one of their trips to South East Asia, Sam and his wife discovered the mangosteen fruit (before it was legal to import it into the U.S.). One of the most exquisite evergreen fruits, also referred to as the Queen of Fruits, the mangosteen is a source of multiple health benefits for the entire human body.

It is segmented into individual fruit seeds, which are packed with flavor and stored safely in a fibrous and firm shell. We adopted this superfruit concept into our solution, which provides a number of benefits to your business. The individual fruit seeds represent the discrete practice areas of the back office operations, supercharged with best-in-class technology and service professionals, under a sturdy and reliable single platform.

We are intentional in everything we do, including selecting the name for our company. We strive to ascribe real purpose to the work we do, transcending the conventional stereotypes of professional etiquette and work-life harmony.

Sam on the Island of Flores, Indonesia

Sam on the Island of Flores, Indonesia (2016)

Book a call