You all got me curious, so I did a little research tonight. Some of this is not new information to all of you, but I wanted to put it all out there to tell the complete story. For most of the historical data, my primary source was the “International Directory of Company Histories”, vol. 24, St. James Press 1999.
Andre Gagey owned vineyards of his own, but from my quick research tonight there appears to be some conflicts among varying sources as to whether he acquired those vineyards or they were- in some measure- inherited. Either way, he did acquire some vineyard land on his own (what he specifically acquired I could not determine) and by marriage he entered into shared ownership of a small Domaine- Domaine Robert Touliere- held by his wife.
In reviewing the vineyard holdings records published in Matt Kramer’s Making Sense of Burgundy, neither the Gagey nor Touliere name appear as owners of Clos St. Denis. I cross checked against NSG Boudots, another Gagey holding, to see if there were any matching names with Clos St. Denis holdings that could suggest a connection- but alas there were none. And so I have not this evening been able to determine when the Gagey family acquired their parcel in Clos St. Denis.
Andre Gagey went to work for Jadot in 1954 and was promoted to a leadership role in 1962. During his tenure, the acquisition of vineyard land and long term lease arrangements were key strategic initiatives at Jadot, and on Gagey’s retirement to the position of chairman in 1992, the holdings of Domaine Andre Gagey were leased to Jadot under such a long term lease arrangement, and presumably the labels carried the Gagey designation from the start of that arrangement (more on that in a moment.)
Attacking the question from the other side, I next reviewed several current resources that would readily give something of a picture as to the history of the official existence of Jadot Clos St. Denis, be it made from Gagey’s holdings or a true negociant bottling.
Winesearcher - a worldwide search of Jadot Clos St. Denis using the Pro version shows listings going back to the 1995 vintage. Further, in the Winesearcher default search terms that come up as you start to enter a wine name, only Jadot Gagey is listed- there is no default search term for Jadot Clos St. Denis without Gagey appended.
Burghound - database shows tastings back to the 1993 vintage.
CellarTracker - for both Louis Jadot Clos St. Denis and Louis Jadot Domaine Gagey Clos St. Denis, ownership listings date back to the 1993 vintage. There are entries for the 1981, 1966 and 1959 for which there are no current or prior holdings, but only auction data. Half the listings refer back to January 18, 2014- and there were Sotheby’s and Acker sales in HK at that time. I searched results for both sales, and while I did come up with 2003 Jadot Clos St. Denis in the Sotheby’s sale, I found no record of these pre-1993 vintages. So either there is a mistake or perhaps these were sold in some less-traveled venue (and perhaps not terribly well vetted- I do not think they exist given the other evidence present.) Also, I would not read anything into the fact there are two separate sets of listings on CT with and without the Gagey name- there are many instances on CT (especially in the German wines) where the same wine is listed under many labels due to some descriptions being more precise.
Finally- I have never seen, heard of, nor tonight could I successfully search for Clos St. Denis- or any wine for that matter- bottled purely under the Gagey name without any Jadot affiliation.
To that end, the evidence suggests that whenever Gagey acquired Clos St. Denis, the grapes or wine were sold to a negociant- and not Louis Jadot- until the 1992 vintage, with the wine as we know it today coming online in 1993.
As for the inconsistent labeling noted in this thread with regards to the Gagey name- my only guess is that this is yet another common example of the fact that rarer wines/formats were often not labeled with great consistency as an economic measure (for example- Roumier magnums have generic red capsules rather than the purplish Roumier capsules on the bottles- or at least they did through at least 2009). And so perhaps in 1996 Jadot ran out of pre-printed Gagey labels (used for various wines) and ran some or all without the name? Or maybe in 1996 there was some purchased fruit added?
Hard to know for sure on this label question, but in my research tonight I did determine that Jadot-Gagey Clos St. Denis is a far rarer wine than I ever suspected. I found one reference to the 2012 in fact that stated “only two barrels” were produced in 2012- which would mean 600 bottles, though I do know some magnums were made as well. In reviewing some of the critical and European retailer write-ups of the vintage as it was sold, it was noted that certain issues cost Jadot as much as half its crop in certain vineyards (I am being deliberately vague rather than risk potentially posting copyrighted material for which I and others pay- even though some of that information is freely posted by merchants and others), which would suggest that at best there are 4 barrels, or the equivalent of about 1,200 bottles, of this wine made annually.
Not a professional or complete bit of research- but hope it is of interest.