He refused to sign anything with her name on it

This is the widest gap between the parts and the whole that this index has recorded, and the explanation comes from the auction house that sold it.

The numbers

From the results recorded here for her: items she signed alone run from $5,978 for a 1961 cheque to $10,800 for an inscribed studio portrait.

His own market is deep and inexpensive by comparison. He signed enormously, and the ordinary certified DiMaggio sits in the hundreds to low thousands.

Add them together and you might reasonably expect something under twenty thousand dollars for an object carrying both.

In August 2021 a baseball signed by the two of them, described as the finest known, sold at Heritage for $384,000.

Roughly twenty-six times the pair of them separately.

Why, in Heritage's own words

The auction house explained it directly in the lot description, and it is worth quoting because it is the mechanism rather than the marketing.

It is well known in the hobby, they wrote, that DiMaggio "flatly refused to sign any piece related to his former wife Marilyn" in the years after her death.

She died in August 1962. He died in March 1999. That is thirty-seven years of a prolific signer declining one specific category of item, for reasons that had nothing to do with the market.

We have written about the four different hands that signed DiMaggio's name, and this was the one thing none of them would touch. Heritage notes that autograph seekers occasionally got Monroe material past him by concealing what he was signing.

So the scarcity is not an accident of survival. It was enforced, deliberately, by one of the two people whose signatures make the object valuable.

The marriage was nine months long

The other half of the supply problem is that the window was tiny.

They married at San Francisco City Hall on 14 January 1954. She filed for divorce on 27 October the same year, citing mental cruelty. Nine months, and they were separated by work for much of it.

Both of the dual-signed results this index has recorded date from 1954. There was not much of a period in which the two of them were routinely in the same room with something to sign.

They remained close afterwards. When she was admitted to a psychiatric clinic in early 1961 it was DiMaggio who secured her release. He arranged her funeral in 1962, and is reported to have sent roses to her grave for the rest of his life.

Which makes the refusal to sign her name a fairly clear statement about what he thought the market was for.

The premium is not automatic

Here is the part that stops this being a simple rule, and it is in our own figures.

The second dual-signed result recorded here is a 1954 Broadway playbill signed by both of them. It made $11,100.

Same two signatures. Same year. Same scarcity argument. A fortieth of the price.

So the premium attaches to the object as much as to the pairing. A baseball is DiMaggio's own medium, the signatures on that example share the sweet spot, and it was described as the finest known example in existence. A playbill is a piece of theatre ephemera that two people happened to write on.

Anybody reading "signed by both" as a guarantee of a six-figure result is reading the wrong variable.

What the wider market says

For context, and because these are all documented results rather than asking prices:

Heritage sold a dual-signed baseball described in the same terms for $191,200 in 2006, a record at the time. Whether that is the same ball as the 2021 lot we cannot say from the descriptions alone, but the direction of travel over fifteen years is clear enough.

Her 1954 passport, carrying four of her signatures including one as Norma Jeane DiMaggio, sold from his estate for $100,000. Their original California marriage certificate, still in its court envelope, made $20,000.

And her wedding ring, estimated at $50,000, sold at Christie's for $772,500. Twice what the baseball made.

The pattern across all of it is that the marriage is the collectible, and the signatures are one way of owning a piece of it.

What to take from this

Three things.

A dual-signed item is its own market, not the sum of two. Pricing it by adding the two signers together will be wrong in both directions, and badly wrong on the objects that matter.

Ask why the scarcity exists. Scarcity from ordinary attrition behaves differently from scarcity somebody created on purpose. His was deliberate, held for thirty-seven years, and is not going to reverse.

And check what it is written on. The forty-fold gap between the baseball and the playbill is entirely about the object. On a market this thin, the medium is doing more work than the names.

The thing worth sitting with

A man refused for thirty-seven years to put his name next to hers on anything, because their marriage had been unhappy and public and he had had enough of both.

The effect of that refusal was to make the few objects carrying both signatures worth more than almost anything else either of them ever touched.

He did not intend it. He sent roses instead.

This index records documented sales of her signed material and tracks his certified market live, with multi-signed items flagged so a figure like the baseball never drags a single-signer average with it. You can read how we work the numbers out.

Sources