Doubt any rumours myself, it's golden factor is that it enhances "Conquest" effect, as they've been known to stack (from the original 10% given while signet/sigil/sanction is on)
although, so I hear it does not stack with [Nation]: Conquest effects
Theres always been a rumor that the hidden effect is Treasure Hunter+1. Another rumor is that for the latent to activate, you must have 1,000,000 or more gil in your inventory.
