The last time the Fed made a surprise move was Jan. 3, 2001 (granted, we were at higher levels and more strained valuations) but, in the 3 trade days after the rate cut of Jan 3rd, 2001, the Nasdaq retraced about 88% of its Jan. 3 gains and the S&P 500 retraced almost all of them.
The volume was huge and there will be more to the upside to come, but some sort of digestion of the gains could happen on Thursday.
Immediate (intraday) support for the Nasdaq is now 2022-1920. The Nasdaq has immediate (intraday) resistance in the 2097-2130 area. On a more intermediate term basis (the next couple of weeks), the Nasdaq is testing a band of considerable resistance 2071-2244. There is a focus of resistance within the 2071-2244 area at 2143-2182.
The S&P 500 has immediate support at 1193-1158. The index has immediate resistance at 1253-1273. Cherney is Market Analyst for Standard & Poor's