I'm not sure if this is significant. This is kind of a follow up to this thread which talks about "Sotheby's cards" and it's unclear what is being referred to.

tl;dr: It appears Sotheby's art institution that Podesta "drew cards" for (whatever that means) is also an international realty firm connected to the house where the handkerchief was found:

• Podesta rented a house in Martha's Vineyard and invited tons of guests to a party there: https://wikileaks.org/podesta-emails/emailid/54496 https://archive.is/xPch4 Address: 55 Harbor View Lane in Vineyard Haven

(There are numerous other emails that talk about this get-together, just search for "vineyard" in wikileaks)

• Searching for this address reveals, among the very first few results, that this house is listed by Sotheby's International Realty: http://www.wallacemv.com/real-estate/55-harbor-view-lane-vineyard-haven-ma-02568/Harbor55/16917472 https://archive.is/vq9ck

• On the website of Sotheby's International Realty, at the bottom of the home page, there's a link to Sotheby's Institute of Art - this means it's the same organization: http://www.sothebysrealty.com https://archive.is/d86Sw

• The widely cited handkerchief email is on Sept 3, 2014 (https://wikileaks.org/podesta-emails/emailid/55433)) which is very shortly after the rental of the house in Martha's Vineyard (Aug 23 2014)

It appears whoever the "realtor" is who found the handkerchief also works for the art institute for which the Podestas were drawing cards ("Sotheby's cards" whatever that really means). This "realtor" sounds like they're in on it, having found the "handkerchief" and thus aware of whatever happened in that house.

Who is the realtor? Could it be an employee or manager at Sotheby's? Could Sotheby's be a one-stop shop for these people? They run real estate, art, and auction businesses, as well as wine and diamond trading.