The company hiding behind the abbreviation LDB&Co. slowly and quietly crept in on me. Years ago, there was nothing to be found online and so I created this page as to make it easier to present the small scraps of information that surfaced now and then. Well, the GMT page started off with even less!
At least it was clear from the start that LDB&Co. was not a manufacturer as their marks appeared on far too many different item groups. For example, one can find LDB&Co. New York markings on metal lamp bases as well as LDB&CO. N.Y. marks in the base of metal clock casings next to a few hints towards patent registrations (cigar lighter, 1928). Its marks are also found on manufacturer-marked items, which would leave the minor possibility of a decoration studio. But there was no difference between items with or without an LDB&Co. mark, and in some cases it was found in combination with a known decoration studio mark.
So no, LDB&Co. was definitely neither a manufacturer nor decoration studio. And that was it, at least for quite some time.
It was not until I received emails from Vickie Costello and Kirstin Greenlaw that I decided to add a little more on the page here as they both brought this one back into my mind and more or less confirmed what had been tickling the back of my brain for ages: LDB&Co. was the company of Leon D. Bloch & Co., an importer of china and glass (as well as trader in furniture and home decor) at one time located at 37-41 E. 18 Street, New York. Even if I do not have any precise dates, this business was around before 1875 and still existed in 1928 (if it survived the 1929 stock market crash and the aftermath thereof is to be doubted).

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Plain "LDB" with a crown over "Germany".

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Round "LDB&Co." mark stating "Czechoslovakia".

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Round "LDB&Co." mark stating "Bavaria" above "Made in Germany". First mark used on items by the Porzellanfabrik Moschendorf.

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Round "LDB&Co." mark stating "Bavarian China", above "Made in Germany".

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Round "LDB&Co." mark stating "Royal Bavaria", above "Made in Germany".

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Crowned round "LDB&Co." mark stating "Prince Regent China" and "Germany" (here with green Moschendorf mark.

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Clearer image of the crowned "LDB&Co., Prince Regent China, Germany" mark on another Moschendorf item.

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Another image of the crowned "LDB&Co., Prince Regent China, Germany".

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Standalone "Princ'e Regent Bavaria" mark.

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Another example of the "Princ'e Regent Bavaria" mark.

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... with the Zell cup mark and the impressed number "2723L".

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Sorry that color and contrast are off a bit, but it is the same item as shown in the first example, only this time ...

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... with the "LDB&Co." mark reading "Hand painted, Made in Germany" next to the impressed number "2723L".
(Pictures by Jean Rogan)

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Made in France by Laviolette (dark green mark, right), handled for "LDB&Co." by Flambeau (light green, left).

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Item with "Limoges France" and Flambeau mark with "LDB&C." included.

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Cover-up mark showing "Flambeau China" and "LDB&Co." above "Limoges, France" and "hand painted".

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Impressed "LDB&Co." above a hand holding a jug or beer stein above "Germany".

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"LDB&Co." mark on a metal part of a lamp.
(Picture: Linda Ziadie)

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"LDB&Co." mark on an item with "Italy" scratched into the base.