Intermountain Precious Metals of Idaho poured 5, 10, and 25 oz ingots with an uppercase “IPM” hallmark — don’t confuse them with the 1960s–70s lowercase “ipm” ingots of the unrelated International Precious Metals of Las Vegas. The tell: Intermountain’s IPM bars have no serial numbers, while the Vegas ones do. Cascade Refining is documented as having produced at least one Intermountain ingot, including an example with an inverted IPM stamp.
Here are two nice examples, including a first generation example from Brian R’s collection.
