Have major billionaires or billionaire groups publicly supported or opposed the bill and why?

1. Who’s loudly backing the Billionaires Income Tax — and what that support actually looks like

Advocacy groups and coalitions have publicly and collectively supported the Billionaires Income Tax Act, mobilizing over 100 organizations and broad public-interest networks framing the bill as closing the “Buy, Borrow, Die” loophole to raise revenue and address inequality; these groups emphasize fairness and investment in families rather than the ultrawealthy. This organized support is institutional and activist rather than composed of named billionaire endorsers in the provided materials. The supporting organizations represent millions of Americans and present estimates that the tax would raise significant revenue from fewer than a thousand households, but the records supplied do not contain direct public statements from individual billionaire figures endorsing the legislation ^{[2] [1]}.

2. Billionaires spending to block local progressive policies — clear opposition by name

In contrast, reporting focused on municipal politics records explicit, named billionaire opposition to progressive candidates and policies: Michael Bloomberg, Ronald Lauder, Joe Gebbia, Bill Ackman, Barry Diller, Laurie Tisch, Steve Wynn, and Alice Walton are listed as donors who publicly funded super PACs to oppose Zohran Mamdani’s mayoral campaign, citing concerns like proposed tax increases and rent controls that they said threatened wealth and business interests. Those actors offered direct financial and public resistance to policies they perceived as economically hostile to their interests, demonstrating an observable pattern of billionaire opposition to redistributive proposals at the city level. The analyses show multi-million-dollar spending aimed at influencing election outcomes and policy trajectories ^{[3] [5]}.

3. Billionaire motives: ideology, self-interest, and post-election rapprochement

The documents reveal a mix of motives behind billionaire engagement: ideological alignment with candidates (as with some supporters of Republican figures), protection of wealth and business models (as with donors opposing tax increases), and pragmatic shifts after electoral outcomes where previously oppositional billionaires offered to engage with newly elected officials. This suggests billionaire behavior is driven by a combination of political ideology and material self-interest, with tactical flexibility when power dynamics change. Analyses note that some financiers who opposed Mamdani later sought meetings and cooperation to address city problems, illustrating how opposition can give way to accommodation once political realities set in ^{[6] [4]}.

4. Missing direct endorsements or denunciations of the federal bill by named billionaires

Across the supplied sources specifically discussing the Billionaires Income Tax Act, there is a notable absence of direct quotes or public statements from named billionaire individuals or billionaire-led foundations explicitly endorsing or condemning the federal bill. Support is documented at the organizational and advocacy level, while named billionaire interventions appear in other contexts, such as municipal elections or partisan backing for presidential figures, rather than this federal tax proposal. The reporting implies billionaire opposition by inference—bill proponents argue the legislation targets billionaire tax practices—but does not provide explicit, attributed billionaire opposition or support tied to the federal bill text ^{[7] [1]}.

5. How different agendas shape the record and reporting on billionaire involvement

The sources reflect distinct agendas: advocacy coalitions frame the tax as corrective and equitable, media reports on municipal politics frame billionaire donors as protecting economic interests, and political analyses note billionaire ideological realignments around national figures. These differing lenses matter because they determine whether the focus is on institutional advocacy for the bill or on billionaire resistance to perceived threats, and they can obscure direct statements from the ultrawealthy about the federal proposal. Readers should note that organizational endorsements do not equal billionaire endorsements, while billionaire-funded opposition is well-documented in local political battles, signaling targeted strategic concerns rather than a unified stance on federal tax legislation ^{[2] [3] [8]}.

6. Bottom line — what the evidence supports and where gaps remain

The available analyses support a clear conclusion that advocacy groups back the Billionaires Income Tax Act and that high-net-worth individuals have publicly opposed redistributive or progressive candidates and policies in other arenas, often by name and with large expenditures. What remains unresolved in these documents is a roster of major billionaires publicly proclaiming support or opposition to this specific federal bill; the record is institutional for supporters and episodic and named for opponents in local politics. Absent statements from billionaire principals in the provided materials, claims about individual billionaire positions on the bill cannot be substantiated beyond inference from related political activity ^{[2] [3] [7]}.