Gold spiked in September 1999 because of the Washington Agreement
After a massive 20 year bear market, gold suddenly spiked from September 21 – October 5 1999. During these 2 weeks, gold soared 32%! This event was purely news driven.
Prior to this event, many European central banks were selling their gold. They believed that gold would never rise again to its 1970s and 1980 levels. Gold went down from May to August 1999 because the UK was selling down its gold reserves. The Swiss National Bank was considering selling its gold, and Australia and the Netherlands were selling as well.
In the Washington Agreement, 11 European central banks agreed on September 26 to limit their selling of gold over the next 5 years (until 2004). This agreement was leaked before September 26, which is why gold started to rise from September 21 – September 24. When the news became public on September 26, gold really started to soar.
As with all news related spikes, this gold spike and retraced 76.4% (the largest Fibonacci Retracement) in 2 months.