Every new New York business filing, every dayHarborstone Group
DEREK MANGI, Registered Agent
Harborstone Group appears to be a business advisory firm specializing in helping owners sell, scale, or plan their exit. The website emphasizes no large upfront retainer and no lock-in contracts, positioning itself as operator-led. The domain directly matches the LLC name, and while the LLC's principal address is in Smithtown, NY, the website lists a New York City office at 450 Lexington Ave.
Filed January 19, 2026 · Smithtown, NY · Suffolk County
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New York Department of State, Division of Corporations · Entity 7810470 · Retrieved May 25, 2026
About Harborstone Group
HARBORSTONE GROUP LLC is a New York business advisory firm filed on January 19, 2026, by owner Derek Mangi, who also acts as the registered agent. The domain was registered 828 days before filing, and the website is a WordPress site. We estimate revenue between $1 million and $10 million and 1 to 5 employees. The company has a brick-and-mortar footprint. No annual report or EIN on file yet.
- Domain registered 828 days before the New York filing date.
- Owner Derek Mangi filed personally as the registered agent.
- We estimate revenue of $1M-$10M and 1-5 employees.
- Website is a WordPress site with a brick-and-mortar footprint.
- No annual report or EIN on file yet.
Compiled from the state record, the company's public web presence, and our own research; revenue, employee, and footprint figures are estimates, not verified financials. Updated August 24, 2026.
One of 36 new businesses registered in Smithtown in January 2026, and the only business advisory business registered there that month.
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Filing Details
Verified Business Profile
Contact Information
Verified Website Profile
We matched this business to its website and pulled the domain's registration (WHOIS) record. Domain age is one of the strongest signals that a filing is a truly new business and not a re-filing or paperwork change.
Frequently Asked Questions
When was Harborstone Group registered?
Harborstone Group was registered as LLC on January 19, 2026 in New York.
Where is Harborstone Group located?
Harborstone Group is based in Smithtown, NY, 11787, in Suffolk County.
What type of business is Harborstone Group?
Harborstone Group is classified as a business advisory business (exit planning and m&a).
Does Harborstone Group have an EIN on file?
No EIN was found on file for Harborstone Group at the time of registration.
Who Sells to This Business
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