It's amazing what you can find on Hebrewbooks!...

In Sifsei Chachamim, by R' Avraham Abba Hertzel (Bratislava, 1899), he says that this is based on the Gemara's statement (Megillah 15b, top) that "that wicked man had all of his treasures engraved on his chest" (evidently meaning that he wore a medallion, or something similar, that had all of his possessions depicted or listed on it). Presumably he would have worn this to the two feasts to which Esther invited him, and since he was taken directly from the second one to be hanged, then that medallion - "all his treasures" in microcosm - was hanging there on the gallows with him.

It's amazing what you can find on Hebrewbooks!...

In Sifsei Chachamim, by R' Avraham Abba Hertzel (Bratislava, 1899), he says that this is based on the Gemara's statement (Megillah 15b, top) that "that wicked man had all of his treasures engraved on his chest" (evidently meaning that he wore a medallion, or something similar, that had all of his possessions depicted or listed on it). Presumably he would have worn this to the two feasts to which Esther invited him, and since he was taken directly from the second one to be hanged, then that medallion - "all his treasures" in microcosm - was hanging there on the gallows with him.