Single Family Office vs Multi Family Office: Bessemer's Turn

A single-family office is a private staff one family hires to run its own money and affairs; a multi-family office is that same staff shared with other families and paid for by all of them. The first buys total control at a fixed cost that never stops. The second trades some control for a cost that scales. The deciding question is complexity, not size.

Henry Phipps knew both sides of that trade. Andrew Carnegie's partner in Carnegie Steel,¹ he came out of the 1901 sale of the company to J.P. Morgan² — the deal that created U.S. Steel³ — among the richest men in America, and with nothing left to run. In 1907 he set up Bessemer Trust,⁴ named for the steelmaking process that had made the money,⁴ to look after his own family's fortune and nothing else.⁵ For decades that is all it did. In 1974 the Phipps family opened the doors to other families,⁴ so the firm could hold the scale needed to attract serious professionals and sustain a full range of services. What ended was exclusivity, not ownership — the founding family kept the firm.⁵ A single-family office became a multi-family office because of arithmetic, not ambition.

The table below sets the three common answers side by side — build a private office, join a shared one, or hire an outside firm to coordinate specialists — for owners who have just sold and are deciding whether to build anything at all. It compares structures and trade-offs, never results.

Build It, Share It, or Rent It: Three Ways to Staff a Fortune

When this table is wrong

The comparison misleads in four situations.

When neither office is warranted. After a sale, the recurring work is often a custodian, a tax adviser and an estate lawyer. A standing institution — owned or rented — carries a floor cost whether or not the work fills a week. The prior question is which tasks actually repeat, and which can stay with specialists hired as needed.

When the real question is governance, not staffing. Families fall out over who decides, not over who files the returns. An office of any type is only as durable as the agreement beneath it: what the pooled money is for, who votes, how a branch leaves. The Pritzker family's experience of keeping wealth together and then dividing it shows how little the structure on top matters once that agreement fails.

When "multi-family office" is a label rather than a structure. The name covers both a firm in the Bessemer pattern — full administration, family-owned, later opened to outsiders — and an investment manager with a planning desk and a product shelf. The test is where revenue comes from. An office paid by the families it serves has one master; one paid by the products it places has two. The questions David Swensen taught endowments to ask a manager apply unchanged: who pays, for what, and what would this firm lose by saying no.

When complexity is confused with size. A cross-border estate, a company still partly owned, or a foundation with its own board can justify dedicated staff that a straightforward portfolio of public stocks and bonds never would. Scale can make a private office affordable; it does not make one necessary.

Use the table as a test of ownership rather than a shopping list. Bessemer's turn is the honest frame: a structure that suited one generation did not suit the next, and the family changed it instead of defending it. Owners choosing now should expect the same reassessment — and should write the exit from whichever structure they pick into its founding papers.