Evelyn Nef was a famed philanthropist. But she wasn’t the District’s $50 million “whale.” (Sarah L. Voisin — The Washington Post)

This post has been updated.

There was no more tantalizing detail in Tuesday’s rollout of the city’s annual financial audit than this: One dead taxpayer is apparently responsible for a $50 million contribution to city coffers — helping to pump estate tax collections $53 million over projections and contributing mightily to an overall surplus of $417 million.

So who was — to borrow a term from the Las Vegas casinos — this “whale”?

City tax officials are keeping a tight lid on the person’s identity, given the nasty penalties for improperly disclosing a taxpayer’s private information. So that leaves us to a rather fun game of parlor speculation.

One name openly floated has been Evelyn Nef, a Georgetown arts patron who died in 2009. At Tuesday’s Q&A Cafe event with Mayor Vincent C. Gray, journalist Carol Joynt mentioned Nef’s name, and a few other folks mentioned it to me Tuesday as a possibility.

But lawyer Michael F. Curtin, who handled Nef’s estate, all but laughed at me when I suggested Nef might have been responsible for the $50 million haul. “A categorical no,” he said.

Curtin, a prominent probate lawyer in town, said it’s hard to fathom such a huge estate tax payout to the city. “It would be a very unusual estate that would be paying $50 million to the District for state estate tax,” he said.

Most people of those means, he suggested, would have tax strategies in place to avoid having to make a payment of that size. (Only D.C. and 16 states have a local estate tax.) Then again, he said, “There are some people who don’t mind paying the taxes. But I don’t know a lot of those kind of people.”

There are some clues to the whale’s species. The District’s estate tax is 16 percent, meaning the deceased would have had a taxable estate of more than $300 million. Also, Curtin said, estate tax is due in almost all cases 10 months after death — meaning the person likely died in August 2011 or thereafter.

One newsworthy death in August 2011 was Viola Drath, the 91-year old Georgetown woman allegedly murdered by husband Albrecht Muth. But there is no indication Drath has anywhere near the sort of wealth that would result in a $50 million estate tax payout.

Over at the Washington Business Journal, reporter Michael Neibauer tossed out a couple of names last year: billionaire developer and sports owner Abe Pollin, and heiress and philanthropist Isabelle Scott. Both died too early; Pollin, furthermore, was a Maryland resident and was survived by his wife, Irene, who would have inherited the estate tax-free.

Any guesses?

Update, 4:05 p.m.: Neibauer has another guess, and it’s a good one: Sidney Harman, the electronics magnate and philanthropist, who died here in April 2011. His net worth, at $500 million, is in the ballpark for a $50 million estate tax payout. And, as an outspoken Democrat, he might just have been one of those people who don’t mind paying taxes.

I’ve sent a note to his widow, former congresswoman Jane Harman, seeking comment.

Updated, 12:45 a.m.: Credit where credit is due — two observers also guessed Harman before Neibauer published his item: Commenter tcfenstermaker and Tweeter Marie Drissel. And I still haven’t heard back from Jane Harman.

Updated, Jan. 31, 10:45 a.m.: Peter Reid, a spokesman for the Woodrow Wilson International Center for Scholars — where Jane Harman is director and CEO — said Thursday, “The speculation is incorrect.”