| FORM | FORMAT | DUE DATE | FILED BY | CONTENT | USE | STATUTE | PENALTY | WAIVER | CONTACT |
| OPM Portal User | User Form | N/A | CEO | User Authorization | To file required reporting in OPM Portal | N/A | N/A | N/A | |
| M-1 | OPM Portal | July 1 | Tax Collector | Mill rate(s) and property tax levies | Various state grant programs; Calculation of total tax levy for State Property PILOT cap | CGS 12-9 and 7-325 | $100 | RCSA 12-9-2 | Christine Goupil |
| M-13 | OPM portal | May 1 | Assessor | Taxable grand list and property exemption data | Equalized Net Grand List (ENGL) calculations; Annual report to the General Assembly | CGS 12-120 | $100 | RCSA 12-120-2 | Christine Goupil |
| M-13a | OPM portal | May 1 | Assessor | Tax exempt grand list data | Annual report to the General Assembly | CGS 12-120 | $100 | RCSA 12-120-2 | Christine Goupil |
| M-35B | Paper report with electronic file submitted to OPM | July 1 | Assessor and Tax Collector | Municipal Claim for Reimbursement - Elderly Homeowners | Grant program; Annual report to the General Assembly | CGS 12-170aa(g) | $250 | RCSA 12-170aa-4 | Patrick Sullivan |
| M-35H | Paper application | February 1 - May 15 | Taxpayer | Elderly Homeowner Application | Grant program; Statute requires submission to Assessor with proof of income | CGS 12-170aa(f) | none | none | Patrick Sullivan |
| M-35P | Paper report | October 1 | Assessor | Reductions to Elderly Homeowners Claim for Reimbursement | Grant purposes | CGS 12-170aa(i) | $250 | RCSA 12-170aa-4 | Patrick Sullivan |
| M-35R | Paper application with electronic submission by municipality | April 1 - October 1 | Taxpayer | Applications for Renter's Rebate | Grant purposes; Statute requires submission to Assessor/Municipal Agent with proof of income and rent/utilities paid | CGS 12-170f | none | none | Patrick Sullivan |
| M-36 | Paper report | Jan 1 | Assessor and Tax Collector | Municipal Claim for Reimbursement - Elderly Homeowner Freeze Program | Grant purposes; Annual report to the General Assembly | CGS 12-129d | $250 | RCSA 12-129d-2 | Patrick Sullivan |
| M-36P | Paper report | Oct 1 | Assessor | Reductions to Freeze Reimbursement | Grant purposes | CGS 12-129b(d) | $250 | RCSA 12-129b-2 | Patrick Sullivan |
| M-36R | Paper application | February 1 - May 15 | Taxpayer | Application for Elderly Homeowner Freeze Program | Grant purposes; Statute requires submission to Assessor with proof of income | CGS 12-129c | none | none | Patrick Sullivan |
| M-37 | OPM Portal | April 1 | Assessor | Report of State Owned Real Property | Grant purposes | CGS 12-19b | $250 | RCSA 12-129b-2 | Christine Goupil |
| M-37C&H | OPM Portal | April 1 | Assessor | Report of Colleges and Hospitals Real Property | Grant purposes | CGS 12-20b | $250 | RCSA 12-20b-2 | Christine Goupil |
| M-42B | Paper report | July 1 | Assessor and Tax Collector | Municipal Claim for Reimbursement - Totally Disabled Program | Grant program | CGS 12-94a | $250 | RCSA 12-94a-2 | Patrick Sullivan |
| M-44/M-44a | Paper Application | Nov 1 | Taxpayer | Tax Exemption Application for Certain Energy Systems | Exemption Application | CGS 12-81 (56), (57), (62), (63) | None | None | Jennifer Gauthier |
| D-1 | Paper application | Prior to date on which Assessor signs Grand List | Taxpayer | Application for Totally Disabled Exemption | Grant purposes; must submit to Assessor with proof of disability | CGS 12-81(55) | None | None | Patrick Sullivan |
| M-45 | OPM portal | Monthly | Assessor and Town Clerk | Data concerning real property transfers | Determination of sales/assessment ratios used in ENGL calculation | CGS 10-261b | $1 per form | RCSA 10-261b-2 | Patrick Sullivan |
| M-46 | OPM Portal | August 1 | Assessor | Municipal Claim for Reimbursement - Distressed Municipality Program | Grant program; Annual report to General Assembly | CGS 32-9s | $250 | RCSA 32-9s-2 | Jennifer Gauthier |
| M-46A | OPM Portal | August 1 | Assessor | Distressed Municipality Program - real property exemptions | Grant purposes; Statute requires submission with Form M-46 | CGS 32-9s | $250 | RCSA 32-9s-2 | Jennifer Gauthier |
| M-46B | OPM Portal | August 1 | Assessor | Distressed Municipality Program - personal property exemptions | Grant purposes; Statute requires submission with Form M-46 | CGS 32-9s | $250 | RCSA 32-9s-2 | Jennifer Gauthier |
| M-55 | Paper application | Nov 1 | Taxpayer | Application - Distressed Municipality Program | Grant purposes; Statute requires annual submission to Assessor | 12-81(59), (60), (70) | none | none | Patrick Sullivan |
| M-59 | Paper report with electronic file submitted to OPM | August 1 | Assessor and Tax Collector | Municipal Claim for Reimbursement - Additional Veterans' Exemption Program | Grant program; Annual Report to General Assembly | CGS 12-81g | $250 | RCSA 12-81g-4 | Patrick Sullivan |
| M-59a | Paper application | Feb 1 - Oct 1 | Taxpayer | Application for Additional Veterans' Exemption | Grant purposes; Regulations require submission to Assessor with proof of income | CGS 12-81g | none | none | Patrick Sullivan |
| MM&E | OPM Portal | May 1 | Assessor | MM&E Exemptions | Annual Report to General Assembly | CGS 12-120c | none | none | Jennifer Gauthier |
| Motor Vehicle Tax Bill | Guidance | N/A | Tax Collector | Municipal Tax Bill Language with Scholarship Fund | Local Option | CGS 12-169a | none | none |