F. B. & Co. Perfin Confirmed; A Likely P. & Co. Perfin Possibility

Roughly two years ago I took a focused look at perfins known to me on the 1898 documentaries.  Most of the perfins I was able to identify.  But the most interesting remained a mystery.  Since early 2023, I've acquired a document that solves one identity completely, and helps point the way to a solution for another.  

The majority of known perfins are relatively simple user initials, and originate from New York.  But there were two that were complex, encoding both user identification and the full date including month, day and year.  The clearest example was P & Co.:

I made the assumption that the above cancel must originate from New York, and likely the stock exchange, leaving the only likely solution the NYSE firm Pearl & Company.  But the known Pearl & Company stock memos of sale with R184 show a simple handstamp cancel and coventional cuts rather than perfins.

The other complex perfin was the partial perfin below with just enough information to show that it was likely similar to the perfin above.  I speculated that the only likely user with the F. B. initial was Finley Barrell & Co. in Chicago:

Now, courtesy of Bob Mustacich, I have a full Finley Barrell & Company futures sale memo from the Chicago Board of Trade, from late in the tax period in 1902:

The memo clearly displays the full complex perfin cancel, which rather than originating in New York as I first thought, came from Chicago.  This style would proliferate and would be a standard for stock sale memos in New York by the time of the World War I tax period.  Finley Barrell & Co's cancel reads as follows:

F. B. & Co.

+6

+6

02

The F. B. & Co. is turned on its side to the 6/6/02 date, indicating that the tax stamps were canceled three days after the original sale.

So I believe it certain that P. & Co. was a Chicago Board of Trade company.  The question is who?  Short of a surviving on-document example, a look at the P. & Co. members of the Board of Trade in 1901 shows only Pickering & Company as the likely user of the cancel.  Please let me know if you have a stamp or document that could confirm or deny this theory.