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Cost of Gas Adjustment Factor Rates and Information

The gas supply rate, or Cost of Gas Adjustment factor (GAF), and the Local Distribution Adjustment factor (LDAF) are semiannual rates charged by regulated Massachusetts gas companies.

Table of Contents

Explanation of Rates

The Cost of Gas Adjustment Factor, or GAF, is the rate charged by regulated gas companies to recover the cost to purchase and transport gas supply to Massachusetts.  

The peak period (or winter) rate is in effect from November 1st through April 30th, and the off-peak period (or summer) rate is in effect from May 1st through October 31st.  

A gas company may, at any time, submit an amended GAF filing to the Department of Public Utilities (DPU). The amended GAF filing must be submitted 7 business days before the first billing cycle of the month in which it is proposed to take effect.  220 CMR 6.12.

The Local Distribution Adjustment Factor, or LDAF, is the rate charged by gas companies to recover distribution-related costs such as energy efficiency, environmental response, Attorney General consultants, residential assistance, and the gas system enhancement replacement program.

For company-specific delivery/distribution rate information, including Revenue Decoupling, please see the DPU's Rates and Tariffs page.

Historical GAF/LDAF rates and data

For GAF and LDAF rates in effect prior to the 2018/19 peak period, please download the GAF Historical Data Workbook.

Peak Period 2018-2019 Rates Revision 3 (Effective 2/1/2019 through 4/30/2019)

Bay State Gas d/b/a Columbia Gas of Massachusetts

Rate Class Billing Unit GAF LDAF
Residential R-1, R-2 $/Therm 0.5659 0.2566
Residential R-3, R-4 $/Therm 0.6447 0.2566
G-40 $/Therm 0.6447 0.1396
G-41 $/Therm 0.6447 0.1020
G-42 $/Therm 0.6447 0.0934
G-43 $/Therm 0.6447 0.0794
G-50 $/Therm 0.5659 0.1396
G-51 $/Therm 0.5659 0.1020
G-52 $/Therm 0.5659 0.0934
G-53 $/Therm 0.5659 0.0794

Berkshire Gas Company

Rate Class Billing Unit GAF LDAF
All Residential  $/Therm 0.7052 0.2064
G-41/G-51 $/Therm 0.7052 0.1298
G-42/G-52 $/Therm 0.7052 0.0971
G-43/G-53 $/Therm 0.7052 0.0714
T-54 $/Therm 0.7052 0.0245

Blackstone Gas Company

Rate Class Billing Unit GAF LDAF
Residential R-1, R-2 $/Ccf 0.8718 0.1619
Residential R-3, R-4 $/Ccf 0.8718 0.1473
G-1, School Rate $/Ccf 0.8718 0.0868

Fitchburg Gas d/b/a Unitil

Rate Class Billing Unit GAF LDAF
Residential R-1, R-2 $/Therm 0.5243 0.3499
Residential R-3, R-4 $/Therm 0.6302 0.3499
G-41 $/Therm 0.6302 0.2555
G-42 $/Therm 0.6302 0.1550
G-43 $/Therm 0.6302 0.1380
G-51 $/Therm 0.5243 0.2555
G-52 $/Therm 0.5243 0.1550
G-53 $/Therm 0.5243 0.1380

Liberty Utilities

Rate Class Billing Unit GAF LDAF
All Residential $/Therm 0.4490 0.3371
G-41, G-42, G-43 $/Therm 0.4490 0.2202
G-51, G-52, G-53 $/Therm 0.4490 0.1646

National Grid - Boston Gas

Rate Class Billing Unit GAF LDAF
All Residential $/Therm 0.6025 0.3138
G-41B/E, G-51B/E $/Therm 0.6025 0.2181
G-42B/E, G-52B/E $/Therm 0.6025 0.2068
G-43B/E, G-53B/E $/Therm 0.6025 0.1898
G-44B, G-54B $/Therm 0.2844 0.1751
G-44B, G-54B $/MDCQ 3.6952  

National Grid - Colonial Gas

Rate Class Billing Unit GAF LDAF
All Residential $/Therm 0.6026 0.2689
G-41, G-51 $/Therm 0.6026 0.1608
G-42, G-52 $/Therm 0.6026 0.1396
G-43, G-53 $/Therm 0.6026 0.1135

NSTAR Gas Company d/b/a Eversource Energy

Rate Class Billing Unit GAF LDAF
All Residential $/Therm 0.6155 0.2257
G-41, G-51 $/Therm 0.6155 0.1184
G-42, G-52 $/Therm 0.6155 0.0871
G-43, G-53, T-1 $/Therm 0.6155 0.0805

Peak Period 2018-2019 Rates Revision 2 (Effective 1/1/2019)

Bay State Gas d/b/a Columbia Gas of Massachusetts

Rate Class Billing Unit GAF LDAF
Residential R-1, R-2 $/Therm 0.7460 0.2660
Residential R-3, R-4 $/Therm 0.8248 0.2660
G-40 $/Therm 0.8248 0.1478
G-41 $/Therm 0.8248 0.1069
G-42 $/Therm 0.8248 0.0974
G-43 $/Therm 0.8248 0.0822
G-50 $/Therm 0.7460 0.1478
G-51 $/Therm 0.7460 0.1069
G-52 $/Therm 0.7460 0.0974
G-53 $/Therm 0.7460 0.0822


Berkshire Gas Company

Rate Class Billing Unit GAF LDAF
Residential R-1, R-2 $/Therm 0.6274 0.1610
Residential R-3, R-4 $/Therm 0.7640 0.1610
G-41 $/Therm 0.7640 0.1039
G-42 $/Therm 0.7640 0.0767
G-43 $/Therm 0.7640 0.0576
G-51 $/Therm 0.6274 0.1039
G-52 $/Therm 0.6274 0.0767
G-53 $/Therm 0.6274 0.0576
T-54 $/Therm 0.6274 0.0164

 

Blackstone Gas Company

Rate Class Billing Unit GAF LDAF
Residential R-1, R-2 $/Ccf 0.8718 0.1619
Residential R-3, R-4 $/Ccf 0.8718 0.1473
G-1, School Rate $/Ccf 0.8718 0.0868

 

Fitchburg Gas d/b/a Unitil

Rate Class Billing Unit GAF LDAF
Residential R-1, R-2 $/Therm 0.5243 0.3897
Residential R-3, R-4 $/Therm 0.6302 0.3897
G-41 $/Therm 0.6302 0.2883
G-42 $/Therm 0.6302 0.1724
G-43 $/Therm 0.6302 0.1526
G-51 $/Therm 0.5243 0.2883
G-52 $/Therm 0.5243 0.1724
G-53 $/Therm 0.5243 0.1526

 

Liberty Utilities

Rate Class Billing Unit GAF LDAF
All Residential $/Therm 0.3642 0.3403
G-41, G-42, G-43 $/Therm 0.3642 0.2228
G-51, G-52, G-53 $/Therm 0.3642 0.1659

 

National Grid - Boston Gas

Rate Class Billing Unit GAF LDAF
All Residential $/Therm 0.6025 0.3138
G-41B/E, G-51B/E $/Therm 0.6025 0.2181
G-42B/E, G-52B/E $/Therm 0.6025 0.2068
G-43B/E, G-53B/E $/Therm 0.6025 0.1898
G-44B, G-54B $/Therm 0.2844 0.1751
G-44B, G-54B $/MDCQ 3.6952  

 

National Grid - Colonial Gas

Rate Class Billing Unit GAF LDAF
All Residential $/Therm 0.6026 0.2689
G-41, G-51 $/Therm 0.6026 0.1608
G-42, G-52 $/Therm 0.6026 0.1396
G-43, G-53 $/Therm 0.6026 0.1135

 

NSTAR Gas Company d/b/a Eversource Energy

Rate Class Billing Unit GAF LDAF
All Residential $/Therm 0.6155 0.2406
G-41, G-51 $/Therm 0.6155 0.1288
G-42, G-52 $/Therm 0.6155 0.0927
G-43, G-53, T-1 $/Therm 0.6155 0.0844

Peak Period 2018-2019 Rates Revision 1 (Effective 12/1/18 through 12/31/18)

Bay State Gas d/b/a Columbia Gas of Massachusetts

Rate Class Billing Unit GAF LDAF
R-1, R-2 $/Therm 0.7460 0.2660
R-3, R-4 $/Therm 0.8248 0.2660
G-40 $/Therm 0.8248 0.1478
G-41 $/Therm 0.8248 0.1069
G-42 $/Therm 0.8248 0.0974
G-43 $/Therm 0.8248 0.0822
G-50 $/Therm 0.7460 0.1478
G-51 $/Therm 0.7460 0.1069
G-52 $/Therm 0.7460 0.0974
G-53 $/Therm 0.7460 0.0822


Berkshire Gas Company

Rate Class Billing Unit GAF LDAF
R-1, R-2 $/Therm 0.6465 0.1610
R-3, R-4 $/Therm 0.7872 0.1610
G-41 $/Therm 0.7872 0.1039
G-42 $/Therm 0.7872 0.0767
G-43 $/Therm 0.7872 0.0576
G-51 $/Therm 0.6465 0.1039
G-52 $/Therm 0.6465 0.0767
G-53 $/Therm 0.6465 0.0576
T-54 $/Therm 0.6465 0.0164

 

Blackstone Gas Company

 

Rate Class Billing Unit GAF LDAF
R-1. R-2 $/Ccf 0.7550 0.1619
R-3, R-4 $/Ccf 0.7550 0.1473
G-1, School Rate $/Ccf 0.7550 0.0868

Fitchburg Gas d/b/a Unitil

Rate Class Billing Unit GAF LDAF
R-1, R-2 $/Therm 0.5243 0.3897
R-3, R-4 $/Therm 0.6302 0.3897
G-41 $/Therm 0.6302 0.2883
G-42 $/Therm 0.6302 0.1724
G-43 $/Therm 0.6302 0.1526
G-51 $/Therm 0.5243 0.2883
G-52 $/Therm 0.5243 0.1724
G-53 $/Therm 0.5243 0.1526

Liberty Utilities

Rate Class Billing Unit GAF LDAF
Residential $/Therm 0.3642 0.3136
G-41, G-42, G-43 $/Therm 0.3642 0.2193
G-51, G-52, G-53 $/Therm 0.3642 0.1624

National Grid - Boston Gas

Rate Class Billing Unit GAF LDAF
Residential $/Therm 0.6025 0.3138
G-41B/E, G-51B/E $/Therm 0.6025 0.2181
G-42B/E, G-52B/E $/Therm 0.6025 0.2068
G-43B/E, G-53B/E $/Therm 0.6025 0.1898
G-44B, G-54B $/Therm 0.2844 0.1751
G-44B, G-54B $/MDCQ 3.6952  

 

National Grid - Colonial Gas

Rate Class Billing Unit GAF LDAF
Residential $/Therm 0.6026 0.2689
G-41, G-51 $/Therm 0.6026 0.1608
G-42, G-52 $/Therm 0.6026 0.1396
G-43, G-53 $/Therm 0.6026 0.1135

 

NSTAR Gas Company d/b/a Eversource Energy

Rate Class Billing Unit GAF LDAF
Residential $/Therm 0.6155 0.2406
G-41, G-51 $/Therm 0.6155 0.1288
G-42, G-52 $/Therm 0.6155 0.0927
G-43, G-53, T-1 $/Therm 0.6155 0.0844

Peak Period 2018-2019 Rates (Effective 11/1/18 through 11/30/18)

Bay State Gas d/b/a Columbia Gas of Massachusetts

Rate Class Billing Unit GAF LDAF
R-1, R-2 $/Therm 0.5694 0.2660
R-3, R-4 $/Therm 0.6482 0.2660
G-40 $/Therm 0.6482 0.1478
G-41 $/Therm 0.6482 0.1069
G-42 $/Therm 0.6482 0.0974
G-43 $/Therm 0.6482 0.0822
G-50 $/Therm 0.5694 0.1478
G-51 $/Therm 0.5694 0.1069
G-52 $/Therm 0.5694 0.0974
G-53 $/Therm 0.5694 0.0822


Berkshire Gas Company

Rate Class Billing Unit GAF LDAF
R-1, R-2 $/Therm 0.5559 0.1610
R-3, R-4 $/Therm 0.6769 0.1610
G-41 $/Therm 0.6769 0.1039
G-42 $/Therm 0.6769 0.0767
G-43 $/Therm 0.6769 0.0576
G-51 $/Therm 0.5559 0.1039
G-52 $/Therm 0.5559 0.0767
G-53 $/Therm 0.5559 0.0576
T-54 $/Therm 0.5559 0.0164

 

Blackstone Gas Company

 

Rate Class Billing Unit GAF LDAF
R-1. R-2 $/Ccf 0.7550 0.1619
R-3, R-4 $/Ccf 0.7550 0.1473
G-1, School Rate $/Ccf 0.7550 0.0868

Fitchburg Gas d/b/a Unitil

Rate Class Billing Unit GAF LDAF
R-1, R-2 $/Therm 0.4453 0.3897
R-3, R-4 $/Therm 0.5512 0.3897
G-41 $/Therm 0.5512 0.2883
G-42 $/Therm 0.5512 0.1724
G-43 $/Therm 0.5512 0.1526
G-51 $/Therm 0.4453 0.2883
G-52 $/Therm 0.4453 0.1724
G-53 $/Therm 0.4453 0.1526

Liberty Utilities

Rate Class Billing Unit GAF LDAF
Residential $/Therm 0.3642 0.3136
G-41, G-42, G-43 $/Therm 0.3642 0.2193
G-51, G-52, G-53 $/Therm 0.3642 0.1624

National Grid - Boston Gas

Rate Class Billing Unit GAF LDAF
Residential $/Therm 0.6025 0.3138
G-41B/E, G-51B/E $/Therm 0.6025 0.2181
G-42B/E, G-52B/E $/Therm 0.6025 0.2068
G-43B/E, G-53B/E $/Therm 0.6025 0.1898
G-44B, G-54B $/Therm 0.2844 0.1751
G-44B, G-54B $/MDCQ 3.6952  

 

National Grid - Colonial Gas

Rate Class Billing Unit GAF LDAF
Residential $/Therm 0.6026 0.2689
G-41, G-51 $/Therm 0.6026 0.1608
G-42, G-52 $/Therm 0.6026 0.1396
G-43, G-53 $/Therm 0.6026 0.1135

 

NSTAR Gas Company d/b/a Eversource Energy

Rate Class Billing Unit GAF LDAF
Residential $/Therm 0.5782 0.2406
G-41, G-51 $/Therm 0.5782 0.1288
G-42, G-52 $/Therm 0.5782 0.0927
G-43, G-53, T-1 $/Therm 0.5782 0.0844

Off-Peak 2018 Rates Revision 2 (Effective 7/1/18 through 10/31/18)

Bay State Gas d/b/a Columbia Gas of Massachusetts

Rate Class Billing Unit GAF LDAF
R-1, R-2 $/Therm 0.2410 0.2392
R-3, R-4 $/Therm 0.3320 0.2392
G-40 $/Therm 0.3320 0.1384
G-41 $/Therm 0.3320 0.0974
G-42 $/Therm 0.3320 0.0880
G-43 $/Therm 0.3320 0.0711
G-50 $/Therm 0.2410 0.1384
G-51 $/Therm 0.2410 0.0974
G-52 $/Therm 0.2410 0.0880
G-53 $/Therm 0.2410 0.0711

Berkshire Gas Company

Rate Class Billing Unit GAF LDAF
R-1, R-2 $/Therm 0.2110 0.1940
R-3, R-4 $/Therm 0.1930 0.1940
G-41 $/Therm 0.1930 0.1030
G-42 $/Therm 0.1930 0.0750
G-43 $/Therm 0.1930 0.0570
G-51 $/Therm 0.2110 0.1030
G-52 $/Therm 0.2110 0.0750
G-53 $/Therm 0.2110 0.0570
T-54 $/Therm 0.2110 0.0140

Blackstone Gas Company

Rate Class Billing Unit GAF LDAF
R-1. R-2 $/Ccf 0.4403 0.1417
R-3, R-4 $/Ccf 0.4403 0.1368
G-1, School Rate $/Ccf 0.4403 0.0668

Fitchburg Gas d/b/a Unitil

Rate Class Billing Unit GAF LDAF
R-1, R-2 $/Therm 0.3336 0.3302
R-3, R-4 $/Therm 0.3345 0.3302
G-41 $/Therm 0.3345 0.2196
G-42 $/Therm 0.3345 0.1241
G-43 $/Therm 0.3345 0.1115
G-51 $/Therm 0.3336 0.2196
G-52 $/Therm 0.3336 0.1241
G-53 $/Therm 0.3336 0.1115

Liberty Utilities

Rate Class Billing Unit GAF LDAF
Residential $/Therm 0.3116 0.3091
G-41, G-42, G-43 $/Therm 0.3116 0.2090
G-51, G-52, G-53 $/Therm 0.3116 0.1517

National Grid - Boston Gas

Rate Class Billing Unit GAF LDAF
Residential $/Therm 0.3547 0.3615
G-41B/E, G-51B/E $/Therm 0.3547 0.2150
G-42B/E, G-52B/E $/Therm 0.3547 0.1864
G-43B/E, G-53B/E $/Therm 0.3547 0.1685
G-44B, G-54B $/Therm 0.2472 0.1472
G-44B, G-54B $/MDCQ 1.1417  

National Grid - Colonial Gas

Rate Class Billing Unit GAF LDAF
Residential $/Therm 0.3529 0.3173
G-41, G-51 $/Therm 0.3529 0.1566
G-42, G-52 $/Therm 0.3529 0.1207
G-43, G-53 $/Therm 0.3529 0.0793

NSTAR Gas Company d/b/a Eversource Energy

Rate Class Billing Unit GAF LDAF
Residential $/Therm 0.2762 0.2412
G-41, G-51 $/Therm 0.2762 0.1473
G-42, G-52 $/Therm 0.2762 0.1085
G-43, G-53, T-1 $/Therm 0.2762 0.1001

Off-Peak 2018 Rates Revision 1 (Effective 6/1/18 through 6/30/18)

Bay State Gas d/b/a Columbia Gas of Massachusetts

Rate Class Billing Unit GAF LDAF
R-1, R-2 $/Therm 0.2782 0.2381
R-3, R-4 $/Therm 0.3692 0.2381
G-40 $/Therm 0.3692 0.1373
G-41 $/Therm 0.3692 0.0966
G-42 $/Therm 0.3692 0.0873
G-43 $/Therm 0.3692 0.0707
G-50 $/Therm 0.2782 0.1373
G-51 $/Therm 0.2782 0.0966
G-52 $/Therm 0.2782 0.0873
G-53 $/Therm 0.2782 0.0707

Berkshire Gas Company

Rate Class Billing Unit GAF LDAF
R-1, R-2 $/Therm 0.3460 0.1940
R-3, R-4 $/Therm 0.3160 0.1940
G-41 $/Therm 0.3160 0.1030
G-42 $/Therm 0.3160 0.0750
G-43 $/Therm 0.3160 0.0570
G-51 $/Therm 0.3460 0.1030
G-52 $/Therm 0.3460 0.0750
G-53 $/Therm 0.3460 0.0570
T-54 $/Therm 0.3460 0.0140

Blackstone Gas Company

Rate Class Billing Unit GAF LDAF
R-1. R-2 $/Ccf 0.4403 0.1417
R-3, R-4 $/Ccf 0.4403 0.1368
G-1, School Rate $/Ccf 0.4403 0.0668

Fitchburg Gas d/b/a Unitil

Rate Class Billing Unit GAF LDAF
R-1, R-2 $/Therm 0.3336 0.3302
R-3, R-4 $/Therm 0.3345 0.3302
G-41 $/Therm 0.3345 0.2196
G-42 $/Therm 0.3345 0.1241
G-43 $/Therm 0.3345 0.1115
G-51 $/Therm 0.3336 0.2196
G-52 $/Therm 0.3336 0.1241
G-53 $/Therm 0.3336 0.1115

Liberty Utilities

Rate Class Billing Unit GAF LDAF
Residential $/Therm 0.3116 0.3091
G-41, G-42, G-43 $/Therm 0.3116 0.2090
G-51, G-52, G-53 $/Therm 0.3116 0.1517

National Grid - Boston Gas

Rate Class Billing Unit GAF LDAF
Residential $/Therm 0.3547 0.3615
G-41B/E, G-51B/E $/Therm 0.3547 0.2150
G-42B/E, G-52B/E $/Therm 0.3547 0.1864
G-43B/E, G-53B/E $/Therm 0.3547 0.1685
G-44B, G-54B $/Therm 0.2472 0.1472
G-44B, G-54B $/MDCQ 1.1417  

National Grid - Colonial Gas

Rate Class Billing Unit GAF LDAF
Residential $/Therm 0.3529 0.3173
G-41, G-51 $/Therm 0.3529 0.1566
G-42, G-52 $/Therm 0.3529 0.1207
G-43, G-53 $/Therm 0.3529 0.0793

NSTAR Gas Company d/b/a Eversource Energy

Rate Class Billing Unit GAF LDAF
Residential $/Therm 0.2762 0.2412
G-41, G-51 $/Therm 0.2762 0.1473
G-42, G-52 $/Therm 0.2762 0.1085
G-43, G-53, T-1 $/Therm 0.2762 0.1001

Off-Peak 2018 Rates (Effective 5/1/18 through 5/31/18)

Bay State Gas d/b/a Columbia Gas of Massachusetts

Rate Class Billing Unit GAF LDAF
R-1, R-2 $/Therm 0.2782 0.2381
R-3, R-4 $/Therm 0.3692 0.2381
G-40 $/Therm 0.3692 0.1373
G-41 $/Therm 0.3692 0.0966
G-42 $/Therm 0.3692 0.0873
G-43 $/Therm 0.3692 0.0707
G-50 $/Therm 0.2782 0.1373
G-51 $/Therm 0.2782 0.0966
G-52 $/Therm 0.2782 0.0873
G-53 $/Therm 0.2782 0.0707

Berkshire Gas Company

Rate Class Billing Unit GAF LDAF
R-1, R-2 $/Therm 0.3460 0.1940
R-3, R-4 $/Therm 0.3160 0.1940
G-41 $/Therm 0.3160 0.1030
G-42 $/Therm 0.3160 0.0750
G-43 $/Therm 0.3160 0.0570
G-51 $/Therm 0.3460 0.1030
G-52 $/Therm 0.3460 0.0750
G-53 $/Therm 0.3460 0.0570
T-54 $/Therm 0.3460 0.0140

Blackstone Gas Company

Rate Class Billing Unit GAF LDAF
R-1. R-2 $/Ccf 0.4403 0.1417
R-3, R-4 $/Ccf 0.4403 0.1368
G-1, School Rate $/Ccf 0.4403 0.0668

Fitchburg Gas d/b/a Unitil

Rate Class Billing Unit GAF LDAF
R-1, R-2 $/Therm 0.3336 0.3302
R-3, R-4 $/Therm 0.3345 0.3302
G-41 $/Therm 0.3345 0.2196
G-42 $/Therm 0.3345 0.1241
G-43 $/Therm 0.3345 0.1115
G-51 $/Therm 0.3336 0.2196
G-52 $/Therm 0.3336 0.1241
G-53 $/Therm 0.3336 0.1115

Liberty Utilities

Rate Class Billing Unit GAF LDAF
Residential $/Therm 0.3116 0.3091
G-41, G-42, G-43 $/Therm 0.3116 0.2090
G-51, G-52, G-53 $/Therm 0.3116 0.1517

National Grid - Boston Gas

Rate Class Billing Unit GAF LDAF
Residential $/Therm 0.3547 0.3615
G-41B/E, G-51B/E $/Therm 0.3547 0.2150
G-42B/E, G-52B/E $/Therm 0.3547 0.1864
G-43B/E, G-53B/E $/Therm 0.3547 0.1685
G-44B, G-54B $/Therm 0.2472 0.1472
G-44B, G-54B $/MDCQ 1.1417  

National Grid - Colonial Gas

Rate Class Billing Unit GAF LDAF
Residential $/Therm 0.3529 0.3173
G-41, G-51 $/Therm 0.3529 0.1566
G-42, G-52 $/Therm 0.3529 0.1207
G-43, G-53 $/Therm 0.3529 0.0793

NSTAR Gas Company d/b/a Eversource Energy

Rate Class Billing Unit GAF LDAF
Residential $/Therm 0.2541 0.2412
G-41, G-51 $/Therm 0.2541 0.1473
G-42, G-52 $/Therm 0.2541 0.1085
G-43, G-53, T-1 $/Therm 0.2541 0.1001

Contact

Phone

Open M-F 9am- 5pm

Online

For questions related to your gas bill GasBilling.Inquiries@mass.gov
For other gas inquiries Non-BillingGas.Inquiries@mass.gov

Address

Department of Public Utilities
One South Station
5th Floor
Boston, MA 02110
Last updated: December 27, 2018
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