The SPDR Gold Trust ETF (NAR:GLD) is having a nice little run, jumping up by about 2.5% over the course of the week. And based on a historically significant indicator, the bull run may continue to trend.

With the day’s session winding down to the closing minutes, GLD sits at $128.39, down 0.25%. That’s a day after it hit a 3-week high. However today, the gold-backed ETF is underperforming the broad market indices, which look like they will end the day stone-cold flat.

GLD, on the other hand, has seriously out-performed the equity indices this year, with the ETF up over 27% since early January. Meanwhile, even though all the major equity indices have hit record highs, with the S&P 500 Index gaining over 7% YTD and the Dow adding over 6%, gold and its related financial vehicles have basically quadrupled those gains.

In terms of the bullish signal for the ETF, that would be the bullish MACD crossover that happened today, sending GLD above the zero line for the first time in over a month. It’s taken a 4-day string of green bars ascending to make it happen, but traders should take note, as the bullish signal has historically proved to be a reliable one.

GLD, as seen in today’s chart, has recently broken out of a short-term range, as defined by support at $127.20 and resistance at $129.25. That support line got breached back on

August 24, and then encountered support at around $125, the lower end of a bigger trading range that began back late June.

So over the last week we’ve seen the ETF bounce off that support, and travel up through the 50-day MA at $127.58. The bounce can continue right through that recent resistance of $129.25 and all the way up to the upper tranche of GLD’s longer-term range of $131, last seen at the height of the Brexit meltdown in late June.

Bottom line: with the MACD indicating an upswing in momentum via the bullish crossover, and its tendency to run in extended uptrends, there might be some room left to run for both the ETF’s underlying commodity as well as for GLD itself.