What specific tax reforms has New York City Councilmember Zohran Mamdani proposed and when were they introduced?

1. What people are saying Mamdani proposed — a concise inventory that cuts through repetition

Multiple recent accounts attribute three main tax measures to Mamdani: a 2% increase in city income tax for earners above $1 million, a proposal to raise the state’s top corporate tax rate from its then‑maximum of 7.25% up toward 11.5%, and a plan to freeze rents for many rent‑stabilized units coupled with a broader property‑tax reallocation aimed at shifting the burden toward wealthier co‑ops and condos. Coverage presents the income surtax and corporate tax hike as numeric proposals with estimated revenue impacts, while the rent‑freeze is framed as a policy lever intended to force a property‑tax overhaul ^{[1] [2] [4]}.

2. When these proposals appeared in public reporting and political debate

The clearest timestamps in the provided material place reporting on the income and corporate tax proposals in late September through early November 2025, with one piece explicitly dated October 30, 2025 and others dated September 24 and November 3, 2025. The rent‑freeze and its connection to property‑tax reform were discussed in August 2025 as part of post‑primary policy positioning. Despite these reporting dates, none of the supplied documents supply a formal bill filing date or legislative docket number that would prove when — or whether — Mamdani officially introduced statutory language in the City Council or State Legislature ^{[1] [2] [3] [4]}.

3. What precisely the proposals would do, according to the coverage

Articles quantify the income surtax as +2 percentage points on city residents earning more than $1 million, projecting roughly $9 billion per year in revenue in one report, and describe a state corporate tax rise to about 11.5% from 7.25% as another revenue source. The rent‑freeze is not a revenue generator in itself but is presented as a fiscal lever: freezing rents would compel the city to rethink property‑tax assessments, reallocating burdens away from large rental properties toward high‑value residential holdings. These figures and mechanisms are consistently reported across the summaries but originate in policy proposals reported by journalists rather than in an identified legislative filing ^{[1] [2] [4]}.

4. Who supports and who opposes — context, comparisons, and political response

Coverage notes immediate political pushback: the state executive branch was reported as unsupportive of the surtax plan by November 2025, and commentators compared the proposals to broader debates about competitiveness and emulation of Nordic tax‑welfare models. Opponents warn of taxpayer flight and business relocation, while proponents argue the surtax and corporate increases would fund expanded services and affordability programs. The rent‑freeze narrative draws particular scrutiny because it links tenant protections with a consequential property‑tax redistribution that would affect owners and municipal revenues, a politically sensitive tradeoff referenced in the reporting ^{[3] [6] [7] [4]}.

5. Gaps, contradictions, and the evidence that matters but is missing

The provided materials show discrepancies and absences: news summaries assert specific rates and revenue estimates but do not point to enacted ordinances, bill texts, or legislative calendars. The Assembly/Council legislative record search found many bills by Mamdani but no explicit property‑tax reform package or statute matching the media descriptions, suggesting the rent‑freeze/property‑tax link is primarily a campaign or platform concept rather than enacted legislation as of the documents’ dates. This means public reporting has named proposals and estimated impacts, but independent verification requires locating formal bill numbers, texts, or legislative sponsorship statements that the supplied sources do not include ^{[1] [2] [5]}.

6. Bottom line: what is established and what to check next

It is established that Mamdani has publicly advocated for an income surtax on million‑dollar earners, a large corporate tax increase, and a rent‑freeze tied to property‑tax shifts; these ideas were reported between August and November 2025 ^{[1] [2] [3] [4]}. What remains unconfirmed in the available material is the formal legislative status: the exact dates of bill introduction, bill numbers, and official sponsorship. To fully verify, consult the New York City Council and New York State legislative databases for filings by Mamdani or allied lawmakers dated late 2024–2025, and review his official press releases for bill texts and introduction dates. ^{[5] [1]}