Gold is having a moment. The metal, tracked by the SPDR Gold Shares (GLD), traded above $4,700 early Monday, its highest level since May 13. August is shaping up to be its best month since September 1999, with prices up roughly 14% so far.

To put that in perspective, the last time gold moved this fast, fifteen European central banks had just signed a pact promising to stop dumping their reserves. Back then, gold rose because governments agreed to stop selling it. This time, the trigger is different: it's fiscal, not monetary.

The Treasury Department's plan to at least double buybacks of long-dated government debt has pushed yields and the dollar lower. That revives demand for assets that can't be printed, like gold. On Monday, the 30-year Treasury yield fell 4 basis points to 4.22%.

So while the 1999 rally was about central banks stepping back, this one is about the government stepping in. Either way, gold investors are smiling.