My thoughts are that it has a lot to do with the USD Index getting smashed today and yesterday... add in that rates are doing the same, and boom, the rich see it as a reason to buy the market... Tie both of these items into the speculation that the Fed will halt rate hikes and boom...
Bottom line: If you count in how much value the USD Index has lost so far this week vs. how much the markets have gained, the market truly is not coming out ahead, and in fact investors haven't even been compensated the full amount of value which was lost via the USD Index...