Mainsail Management Inc.

• Established: 1981
• Experience: Over four decades of activity in the Massachusetts real estate market
• Portfolio: Residential and commercial properties, with a strong emphasis on high-end urban housing
• Specialties:
• Condominium conversions
• Luxury renovations of historic brownstones
• New construction condominium buildings
• Acquisition, repositioning, and management of rental properties

Mainsail is especially active in Boston neighborhoods such as Back Bay, Beacon Hill, the South End, Bay Village, and surrounding areas including Brighton, Brookline, and Dorchester.

Over the course of its history, the company and its principals have completed over 125 condominium conversions in prime Boston locations and have undertaken numerous additional development and renovation projects across Greater Boston and New England.

Investment partners

For more than twenty years, Mainsail Management has worked with a group of trusted investors on a wide range of projects. These long-term relationships are based on:

• A consistent focus on identifying strong real estate opportunities
• Hands-on involvement from acquisition through stabilization or sale
• A track record of delivering positive returns over time (specific investment performance figures and guarantees are not published here).

Leadership and team

Mainsail Management is led and supported by a team with extensive real estate and construction experience, including:

• Jim Keliher – President

Founder and principal of Mainsail Management. Jim began in real estate in 1980 by renting apartments before moving into purchasing and revitalizing properties, particularly in Back Bay, and later expanding into commercial properties across Boston.

• Ben Whitney – Vice President
• Tom Helms – Head of Construction
• David Roe – Director of Maintenance
• Dorene Ambrose – Property Manager
• Meghan Keliher – Assistant Property Manager
• Jackie Keliher – Assistant Acquisitions Manager
• Jocelyn Perez – Accounting

This in-house team allows Mainsail Management to oversee the full lifecycle of a project—from acquisition and design through construction, leasing, and ongoing property management.

Mainsail provides property management services designed to support both resident satisfaction and sound operations for owners and investors.

Key aspects include:

• Day-to-day oversight of residential and mixed-use properties
• Coordination of maintenance and repairs through Mainsail's in-house maintenance team
• Attention to building appearance, common areas, and building systems
• Support for stable occupancy and long-term asset value

(Details such as specific management fees, lease terms, and tenant policies are not published here.)

Investments and acquisitions

Mainsail Management identifies, evaluates, and acquires properties with the potential for value creation through renovation, repositioning, or new development.

Typical activities include:

• Sourcing and underwriting investment opportunities in Greater Boston and surrounding markets
• Acquiring multifamily, mixed-use, and select commercial properties
• Working with long-term investment partners on capital structure and project strategy

Specific investment returns, forecasts, or guarantees are not published here.

Development

Mainsail has extensive experience with both renovation projects and new construction in urban settings.

Development work includes:

• Converting existing buildings into condominiums or upgraded rental housing
• Renovating historic brownstones and townhouses in neighborhoods such as Back Bay, the South End, Beacon Hill, and Bay Village
• Developing new construction condominium buildings in markets such as Brighton and other Boston neighborhoods

Projects range from small, high-end residential buildings to larger multi-unit condominium developments.

Construction (in-house capabilities)

Mainsail's construction activities are led by an in-house team of skilled craftsmen under the direction of the Head of Construction.

Construction capabilities include:

• Full gut renovations of historic brownstones
• High-end finishes and custom millwork
• Capital improvements and upgrades at rental properties
• Coordination of building systems, exterior improvements, and code compliance

This integrated construction team allows Mainsail to closely control quality, schedule, and design details across its development and renovation projects.

• Business name: Mainsail Management Inc.
• Address: 251 Newbury St, Boston, MA 02116

This office is located in Boston's Back Bay neighborhood.

Contact information

• Email: info@mainsailmgmt.com
• Phone: 617-267-5575

If you need assistance with a property managed or developed by Mainsail Management, or if you are inquiring about potential investment or development opportunities, you can reach the office using the contact details above.

(Individual staff email addresses or direct lines are not published here.)

Office hours

• Regular office hours: Monday – Friday, 10:00am – 6:00pm

These hours refer to the main office. Availability outside these times is not specified here. For urgent matters outside regular hours, please contact Mainsail Management using the published phone number or email, and the team will respond according to their internal procedures.

117 Beacon Street, Back Bay, Boston

A landmark Back Bay property located just steps from the Public Garden and Charles River.

• Conversion of a former single-family home into two ultra-luxury 4-bedroom homes with garage parking
• Unit One: approximately 3,000+ SF, 4 beds, 4.5 baths, 1 garage parking space
• Penthouse residence: over 5,000 SF, 4 bedrooms plus library, private elevator, 2 garage parking spaces, and a private roof deck

142 Beacon Street, Back Bay, Boston

A rare riverfront property on Beacon Street with long views over the Charles River Esplanade.

• Three luxury residences across approximately 10,000 SF and seven floors
• Ceilings up to approximately 13 feet
• Each home includes private walk-out outdoor space
• New parking garage with direct elevator access to each unit
• New limestone façade with period details and an elegant entry foyer

170 West Brookline Street, South End, Boston

A luxuriously renovated single-family residence in Boston's historic South End.

• Approximately 4,000+ SF across multiple levels
• Residential elevator serving all floors
• High-end custom kitchen and statuary marble master bath
• Floor-to-ceiling glass walls in key living areas
• Private roof deck with custom lighting
• Heated driveway and additional outdoor parking

Additional representative projects by neighborhood

Below is a non-exhaustive selection of projects mentioned in Mainsail's portfolio, grouped by neighborhood. Descriptions and unit counts are based on the portfolio summary and may be further detailed in project-specific materials.

Back Bay, Boston

• 117 Beacon Street – 2 luxury condominium residences converted from a single-family home
• 142 Beacon Street – 3 luxury condominiums in a riverfront limestone building
• 476 Beacon Street – 4 luxury condominium residences
• 67 St. Botolph Street – 4 luxury condominiums
• 249 Newbury Street – mixed-use building with 2 residential luxury condominiums and 2 commercial condominiums

South End, Boston

• 170 West Brookline Street – single-family residence (luxury renovation)
• 166 West Brookline Street – 2 luxury condominiums
• 89 Pembroke Street – 2 luxury condominiums
• 60 West Rutland Square – 2 luxury condominiums
• 39 Greenwich Park – single-family residence
• 25 Concord Square – 2 luxury condominiums in a gut-renovated building
• 156 West Concord Street – 2 luxury condominiums
• 517–519 Shawmut Avenue – 4 ground-up luxury condominiums

Beacon Hill and Bay Village, Boston

• 94 Chestnut Street, Beacon Hill – 2 luxury condominiums following an artful restoration
• 67–71 West Cedar Street, Beacon Hill – 5 luxury condominiums created from a larger number of smaller units
• 11 Melrose Street, Bay Village – contemporary 3-family home with distinctive modern design and extensive glazing

Other Boston neighborhoods and nearby communities

• 99 Tremont Street, Brighton – 62-unit new construction condominium building (collaborative project)
• 69 Bailey Street, Dorchester – 21 rental apartments
• 178 Thornton Street, Roxbury – new construction with 4 condominium residences
• 25 Alton Court, Brookline – 4 luxury condominiums
• 105 Winthrop Road, Brookline – 4 luxury condominiums

Notable repositioning and entitlement projects

• 761 Harrison Avenue, South End, Boston (Immaculate Conception Church) – historic church property purchased, permitted for approximately 60 apartments, and sold after entitlement

Notes

• The list above is illustrative, not complete.
• Specific availability, current pricing, and current ownership status of any property are not published here. For up-to-date information on available units or new projects, please contact Mainsail Management directly.

Ask anyway — the agent will say plainly that it is not published rather than guess.