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   We are committed to upholding the principles of all applicable fair housing laws

Boutique Real Estate. Elevated  Standards.

The Σ of SUCCESS

Our mission is to deliver the ultimate Σ of Success — through precision, integrity, and a truly personalized approach to real estate. Every client’s journey is unique, and every detail matters. We blend expertise with empathy, transforming vision into lasting value. Because at Sigma Group, success is not defined by transactions — it’s built through relationships, elevated by excellence, and designed to endure.

36

Closed Sales

$24.4M

Total Value

$307K - $1.6M

Price Range

$677K

Average Price

Meet

Stacey Tzortzatos

Broker & Owner of Sigma Group Real Estate

Stacey Tzortzatos is the Broker and Owner of SIGMA GROUP Real Estate — but more than that, she’s someone who truly loves helping people find their place in the world. Stacey makes every client feel heard and supported from the first conversation to the closing table. With a deep knowledge of the local market and a talent for creating smooth, stress-free experiences, she tailors her approach to fit each client’s unique needs — whether you’re buying your first home, selling your property, or navigating a difficult situation. Her goal is simple: to make real estate feel personal, approachable, and rewarding every step of the way.

License
#10401289392
Meet

THE TEAM

With a data driven approach, exceptional negotiation skills, and expertise of the housing market, our team delivers results that drive your success. Discover the professionals setting a new standard for real estate in New York.
See Why Our Clients Love Us

Testimonials

Read what our clients have to say about working with us.

"Stacy was very professional throughout the whole brokerage process. She was clear in communication and straightforward in regards to any potential issues that may impede the sale. Thank you, Stacy, for enabling a fair and smooth transaction."
"Stacy was very professional throughout the whole brokerage process. She was clear in communication and straightforward in regards to any potential issues that may impede the sale. Thank you, Stacy, for enabling a fair and smooth transaction."
Brian L.
"Working with Stacey to sell my father’s home was a true blessing during a very emotional and high-stakes process. From start to finish, she was professional, patient, and relentless in her commitment to getting the best outcome for my family. Her communication was always clear and timely, and she handled every detail with integrity and care. She guided us through a complex sale with multiple parties involved, and made sure everything stayed on track—even during the most stressful moments. I never once felt in the dark or alone in the process. Now that she’s opening her own brokerage, I have no doubt she’ll bring the same dedication and excellence to every client. I’m incredibly grateful for her hard work and would recommend her without hesitation. Thank you again for everything!"
"Working with Stacey to sell my father’s home was a true blessing during a very emotional and high-stakes process. From start to finish, she was professional, patient, and relentless in her commitment to getting the best outcome for my family. Her communication was always clear and timely, and she handled every detail with integrity and care. She guided us through a complex sale with multiple parties involved, and made sure everything stayed on track—even during the most stressful moments. I never once felt in the dark or alone in the process. Now that she’s opening her own brokerage, I have no doubt she’ll bring the same dedication and excellence to every client. I’m incredibly grateful for her hard work and would recommend her without hesitation. Thank you again for everything!"
John S.
"Extremely friendly and a pleasure to work with."
"Extremely friendly and a pleasure to work with."
Leon F.
"We can’t recommend Stacey Tzortzatos highly enough! She helped my wife, Kelsey, and me find our forever home in just three weeks, and we were able to close incredibly quickly thanks to her expertise and efficiency. Throughout the process, Stacey’s communication was always smooth and clear, and she handled every challenge with professionalism and grace. She consistently made us feel comfortable, valued, and cared for—something that truly set her apart. Her knowledge of the area and sharp negotiation skills helped us land the perfect deal. On closing day, she went above and beyond by surprising us with thoughtful gifts for our new home, making the day even more special. What truly stood out was how much Stacey genuinely cared about finding the perfect house for us. She wasn’t just our realtor—she was our advocate and partner throughout the journey. If you’re looking for someone who is dedicated, compassionate, and incredibly skilled, Stacey is the one you want by your side."
"We can’t recommend Stacey Tzortzatos highly enough! She helped my wife, Kelsey, and me find our forever home in just three weeks, and we were able to close incredibly quickly thanks to her expertise and efficiency. Throughout the process, Stacey’s communication was always smooth and clear, and she handled every challenge with professionalism and grace. She consistently made us feel comfortable, valued, and cared for—something that truly set her apart. Her knowledge of the area and sharp negotiation skills helped us land the perfect deal. On closing day, she went above and beyond by surprising us with thoughtful gifts for our new home, making the day even more special. What truly stood out was how much Stacey genuinely cared about finding the perfect house for us. She wasn’t just our realtor—she was our advocate and partner throughout the journey. If you’re looking for someone who is dedicated, compassionate, and incredibly skilled, Stacey is the one you want by your side."
Dennis M.
"Stacey is truly an incredible person and realtor inside and out! She is a strong advocate, and she is extremely knowledgeable in her profession. We can always rely on her to guide us in the proper direction, help us make important decisions, and get the job done timely and effectively! She is a kind-hearted person who treats her clients the way she would treat her own family. We have gained another family member through this process. Without Stacey, we wouldn’t have been able to sell our home and purchase our new one. She made the whole process seamless!"
"Stacey is truly an incredible person and realtor inside and out! She is a strong advocate, and she is extremely knowledgeable in her profession. We can always rely on her to guide us in the proper direction, help us make important decisions, and get the job done timely and effectively! She is a kind-hearted person who treats her clients the way she would treat her own family. We have gained another family member through this process. Without Stacey, we wouldn’t have been able to sell our home and purchase our new one. She made the whole process seamless!"
Cristina T.
"Stacey is an amazing realtor. She really made it happen for me and my family. You need someone like her on your corner to fight for you. My dream house has come true!!! She was always there for me when I needed her. Help me all the way in every step of the way. Highly recommend her. I wish I could give her 10."
"Stacey is an amazing realtor. She really made it happen for me and my family. You need someone like her on your corner to fight for you. My dream house has come true!!! She was always there for me when I needed her. Help me all the way in every step of the way. Highly recommend her. I wish I could give her 10."
Hokychie T.
"Stacey was attentive and responsive during our real estate transaction. She made herself available whenever my husband and I had questions about the property. I highly recommend using her professional services!"
"Stacey was attentive and responsive during our real estate transaction. She made herself available whenever my husband and I had questions about the property. I highly recommend using her professional services!"
Karen S.
"Words can't be enough to express our gratitude and appreciation towards Stacey. After a terrible experience we had with our previous realtor, Stacey came to our rescue and took over selling our condo, and in no time, professional pictures were taken and the house was on the market within a few days. She had strict guidelines as to which buyers were serious about buying, and only those who came over and checked our place. With COVID still around and having a newborn at home, we really appreciated that. Within a few days, we had multiple offers, and we accepted one of them. After we signed the contracts, she was on top of every little detail to make sure the whole process was as smooth as it could possibly be. All the way till the closing. She made sure we always knew where we were in the process, and she was always available to answer any questions we had. That made us feel very safe. I can't recommend Stacey enough. We couldn't be happier with her excellent work ethic and professionalism. I will be recommending her whenever I get the opportunity. Having the right real estate agent makes a big difference when you sell or buy a home. I have been buying and selling a few homes so far, dealing with a few realtors, but Stacey has been by far the most exceptional one. Thank you, Stavey, from me, Brittany, and little Cassie!"
"Words can't be enough to express our gratitude and appreciation towards Stacey. After a terrible experience we had with our previous realtor, Stacey came to our rescue and took over selling our condo, and in no time, professional pictures were taken and the house was on the market within a few days. She had strict guidelines as to which buyers were serious about buying, and only those who came over and checked our place. With COVID still around and having a newborn at home, we really appreciated that. Within a few days, we had multiple offers, and we accepted one of them. After we signed the contracts, she was on top of every little detail to make sure the whole process was as smooth as it could possibly be. All the way till the closing. She made sure we always knew where we were in the process, and she was always available to answer any questions we had. That made us feel very safe. I can't recommend Stacey enough. We couldn't be happier with her excellent work ethic and professionalism. I will be recommending her whenever I get the opportunity. Having the right real estate agent makes a big difference when you sell or buy a home. I have been buying and selling a few homes so far, dealing with a few realtors, but Stacey has been by far the most exceptional one. Thank you, Stavey, from me, Brittany, and little Cassie!"
Michalis V.
"If you are looking to buy your dream house, please don't look any further. Stacey from KW is an amazing person with a good heart and is very knowledgeable in the Real Estate business. She helps us find our dream home. She answered all our questions with patience and was always available whenever we needed her. We truly had an amazing experience, and we highly recommend Stacey to anyone. Stacey, keep up the good work! We will let you know when we are ready for our next home!"
"If you are looking to buy your dream house, please don't look any further. Stacey from KW is an amazing person with a good heart and is very knowledgeable in the Real Estate business. She helps us find our dream home. She answered all our questions with patience and was always available whenever we needed her. We truly had an amazing experience, and we highly recommend Stacey to anyone. Stacey, keep up the good work! We will let you know when we are ready for our next home!"
Buyer
"Great person to work with!"
"Great person to work with!"
Kamrojjman B.
"James is very professional and knowledgeable. He is always available and kept open, honest communication with us as we were selling our home. He made what could have been a stressful and difficult process as seamless as could be. We truly had an excellent experience with James. He went above and beyond to sell our home. We highly recommend him."
"James is very professional and knowledgeable. He is always available and kept open, honest communication with us as we were selling our home. He made what could have been a stressful and difficult process as seamless as could be. We truly had an excellent experience with James. He went above and beyond to sell our home. We highly recommend him."
Seller
"James is the best! Hands down! Professional, friendly, caring and knowledgeable about the area, the process, the benefits and the pitfalls. James guided us smoothly through what can typically be a difficult and emotional time. He helped us understand the market price for our home, write up an accurate description of the house had a photographer take professional photos, had it listed and showed our open house with without causing unnecessary stress to us and with true professionalism. James guided us through the negotiating process with the new buyers and he recommended an excellent legal professional (Alex) for closing. We very highly recommend James to anyone looking to sell or buy a home."
"James is the best! Hands down! Professional, friendly, caring and knowledgeable about the area, the process, the benefits and the pitfalls. James guided us smoothly through what can typically be a difficult and emotional time. He helped us understand the market price for our home, write up an accurate description of the house had a photographer take professional photos, had it listed and showed our open house with without causing unnecessary stress to us and with true professionalism. James guided us through the negotiating process with the new buyers and he recommended an excellent legal professional (Alex) for closing. We very highly recommend James to anyone looking to sell or buy a home."
Joel R.
"I employed James to sell my home. James was a pleasure to work with and easy going. He was very knowledgeable, professional and willing to go the extra mile to help sell my home. He held 2 open houses to help sell it, even though I was in another state. I felt very comfortable allowing him to oversee the open houses, and the security of my home. Highly recommend him to all. Thanks again James."
"I employed James to sell my home. James was a pleasure to work with and easy going. He was very knowledgeable, professional and willing to go the extra mile to help sell my home. He held 2 open houses to help sell it, even though I was in another state. I felt very comfortable allowing him to oversee the open houses, and the security of my home. Highly recommend him to all. Thanks again James."
Eric
"I employed the services of James when I started looking for a home to purchase. James is very accommodating, professional, and helpful. This is my first time looking to purchase a home, and James has been very patient and helpful with my questions. I have already recommended James to friends of mine looking to buy a house and will continue to do so. Thanks James!"
"I employed the services of James when I started looking for a home to purchase. James is very accommodating, professional, and helpful. This is my first time looking to purchase a home, and James has been very patient and helpful with my questions. I have already recommended James to friends of mine looking to buy a house and will continue to do so. Thanks James!"
Buyer | Seller
"Mr. Karalis is a knowledgeable, responsive, and experienced agent who helped us list and rent the upstairs apartmant in my home. What we liked most about Mr. Karalis is his true dedication and work ethics. He answered our calls even after hours and was very helpful. He was very thorough and checked all references from all possible tenants. We highly recommend James Karalis to our family and friends and guarantee a very positive experience."
"Mr. Karalis is a knowledgeable, responsive, and experienced agent who helped us list and rent the upstairs apartmant in my home. What we liked most about Mr. Karalis is his true dedication and work ethics. He answered our calls even after hours and was very helpful. He was very thorough and checked all references from all possible tenants. We highly recommend James Karalis to our family and friends and guarantee a very positive experience."
Anthony K.
"James is thorough and professional. He did a lot more for me than I ever expected from a realtor. I appreciated how he was on top of things and how he kept me informed every step of the way. I also appreciated James's integrity and patience, which are virtues that I find most commendable in a realtor."
"James is thorough and professional. He did a lot more for me than I ever expected from a realtor. I appreciated how he was on top of things and how he kept me informed every step of the way. I also appreciated James's integrity and patience, which are virtues that I find most commendable in a realtor."
Buyer
"James has been a true professional with me and my family. James showed me homes in the great neck area. He only showed me things that were in my price range and did not pressure me into anything. I highly recommend James to anyone looking to buy a home. Thank you."
"James has been a true professional with me and my family. James showed me homes in the great neck area. He only showed me things that were in my price range and did not pressure me into anything. I highly recommend James to anyone looking to buy a home. Thank you."
Brice
"When my whole family moved from west coast to NY, we had known nobody in NY, and it was just a venture for us. Fortunately, we found James as our home buying agent. James didn't even helped us buying our new home, he had voluntarily helped us settling down in NY in good shape. He had patiently guided us the entire process for over half a year since we started to think of moving to NY from the west. We had faced various challenges in our move and home purchase, thanks James for assisting us solving all those problems."
"When my whole family moved from west coast to NY, we had known nobody in NY, and it was just a venture for us. Fortunately, we found James as our home buying agent. James didn't even helped us buying our new home, he had voluntarily helped us settling down in NY in good shape. He had patiently guided us the entire process for over half a year since we started to think of moving to NY from the west. We had faced various challenges in our move and home purchase, thanks James for assisting us solving all those problems."
Elaine
"My interaction with James was a positive and very professional experience. James was prompt. He was always available and returned all phone calls in a timely fashion. He represents your company very well. I would recommend James to my friends."
"My interaction with James was a positive and very professional experience. James was prompt. He was always available and returned all phone calls in a timely fashion. He represents your company very well. I would recommend James to my friends."
Tommy
"I've moved 4 times prior to this and I have never felt like I was in more capable hands. Whenever there was a problem, James would take care of it and I never had to worry. It was the most professional experience. Selling one's house can be a highly stressful event I would know from the experience of dealing with it one too often, but James has the unique ability to alleviate the burdens that come with selling one's home. All in all, a truly rewarding experience. Thank you James!"
"I've moved 4 times prior to this and I have never felt like I was in more capable hands. Whenever there was a problem, James would take care of it and I never had to worry. It was the most professional experience. Selling one's house can be a highly stressful event I would know from the experience of dealing with it one too often, but James has the unique ability to alleviate the burdens that come with selling one's home. All in all, a truly rewarding experience. Thank you James!"
Seller

Browse Our

Current Listings

Explore our active properties below or contact us to schedule a private showing.

  • Luxury Home In Nassau County Pending

    $1,499,000

    30 Knoll Lane, Glen Head, NY 11545

  • 14956 20th Ave For Sale

    $1,028,000

    14956 20th Ave, Whitestone, NY 11357

    • 4 Beds
    • 2.5 Baths
    • 1,456 Sq.Ft.
  • 747 N Broadway 2 For Lease

    $3,500/mo

    747 N Broadway 2, Massapequa, NY 11758

    • 2 Baths
View All Properties

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Areas of Expertise

Neighborhoods

Browse our lifestyle guides to learn about the best neighborhoods for you.

  • Astoria
  • Bayside
  • Flushing
  • Glen Cove
  • Mineola
  • Roslyn
  • Whitestone

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