# Willett Advisors

Willett Advisors is a Single Family Office based in New York, United States.

## Overview

- **Organization type:** Single Family Office
- **Headquarters:** New York, United States
- **Region:** North America
- **Address:** New York, NY, United States
- **Founded:** 2010
- **Assets under management:** Undisclosed
- **Website:** willettadvisors.com
- **LinkedIn:** https://www.linkedin.com/company/willett-advisors-llc/about/
- **Wikidata:** Q42393368

## Regulatory record

- **Reports private funds:** No

## About

Willett Advisors was established in 2010 to oversee the wealth generated by Bloomberg L.P. and its founder, Michael R. Bloomberg. Steven Rattner serves as Chairman and CEO, with Andrew Mulderry as Chief Investment Officer. The firm invests both personal holdings and assets directed through Bloomberg Philanthropies. The portfolio spans public equities, private equity buyouts and growth equity, real estate, hedge funds, and direct co-investments. Confirmed positions include Circle Internet Financial and a stake in White Star Petroleum. The firm also holds exposure to oil and gas assets through Geotech Oil Services and has participated alongside Sycamore Partners. Geographic coverage centers on North America with additional activity in Europe and Asia. Investment stages range from seed and Series A through Series G and into buyouts. Team size and office footprint remain undisclosed beyond the New York headquarters. Willett maintains memberships in the Council on Foreign Relations, Economic Club of New York, and Partnership for New York City. Michael Bloomberg is a signatory to The Giving Pledge. No operational events from the last 24 months appear in public records. The office functions as a dedicated vehicle for one principal's capital with direct oversight by Rattner, who previously co-founded Quadrangle Group. This creates a governance model that integrates investment execution with Bloomberg's broader philanthropic and policy interests without external LP reporting requirements.

## Sectors

- FinTech
- Digital Health
- ClimateTech
- Energy Transition & Renewables
- LegalTech
- AI/ML
- Enterprise Software
- Web3 & Blockchain

## People

- Michael R. Bloomberg — Founder
- Steven Rattner — Chairman & CEO
- Andrew Mulderry — Chief Investment Officer

## Questions

### Who runs investment decisions at Willett Advisors?

Steven Rattner serves as Chairman and CEO. Andrew Mulderry acts as Chief Investment Officer and oversees both public and private market allocations.

### How is Willett Advisors related to Bloomberg Philanthropies?

Willett manages capital that supports Bloomberg Philanthropies initiatives. The two entities share the same ultimate beneficial owner but maintain separate operational structures.

### Does Willett Advisors participate in fund commitments or only direct deals?

The firm uses a mix of fund commitments, hedge fund allocations, and direct co-investments. Confirmed direct holdings include Circle Internet Financial and a White Star Petroleum stake.

### What investment stages does Willett Advisors target?

The firm covers seed through Series G rounds as well as buyouts and growth equity. It also maintains allocations to real estate and hedge funds.

### Which sectors does Willett Advisors focus on?

Documented sector exposure includes FinTech, Digital Health, ClimateTech, Energy Transition & Renewables, LegalTech, AI/ML, Enterprise Software, and Web3 & Blockchain.

### Does Willett Advisors maintain club memberships or external affiliations?

The firm and its principals hold memberships in the Council on Foreign Relations, Economic Club of New York, Partnership for New York City, Century Country Club, Harmonie Club, Brook Club, and Racquet and Tennis Club.

## Related profiles

- [Reuben Brothers](https://altss.com/profile/reuben-brothers-reuben-family-office)
- [Ascent Private Capital Management](https://altss.com/profile/ascent-private-capital-management)

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Source record modified: 2026-08-10T15:54:10.904Z

Last verified: not supplied by this public snapshot.

## Sources and provenance

- Organization website as recorded: https://willettadvisors.com/
Source links do not imply that every field was verified on the page modification date. See [Altss methodology](https://altss.com/methodology).

Canonical page: https://altss.com/profile/willett-advisors-michael-bloomberg-family-office

Maintained by Altss — https://altss.com — methodology: https://altss.com/methodology