From 3/28 SPY post: "Nothing wrong with SPY here; light volume selling. Red line is 2015 close, so further moves above that may generate more buying."
So SPY went green and this prompted further buying / short covering in IWM as well. It was also a big deal for NDX / QQQ to have a huge day, because that means bullish launch from the cash index YP. This very successfully re-tested in the last 3 trading days.
GLD / GDX also benefited from Yellen's ulta-dovish speech today - possibility of QE4! So idea to hold GLD above the MarP worked out. GLD should remain above the YR1 from here.
The only thing to temper the bullishness is the stealth rally in TLT. It is back above all pivots and remains the strongest overall trend in the market.
SPY, NDX and GLD below.