Year to Date the S&P 500 Index is up 26.8%. However through Friday Dec. 27th, the index is down 1% for the month. What has happened in other years similar?
Looking at years where the S&P 500 Index is up greater than 15% ytd, but December finished with a negative month; here are the stats (both since 1901 and Post-WW-II). Not a death knell for the following year. Actually, post-WW II, only 1 out of 6 instances finished down. Average = +7.7%, 83% positive. The one exception was 1980, when Reagan was elected. He was a disruptive, less Govt, pro-biz President like Trump has promised to be. However, inflation (12.8%), interest rates (10-yr = 12.7%) and unemployment (7.5%) were much higher and Fed Chairman Paul Volker raised the Fed Funds rate from 9.5% to 20% the following year to kill inflation, throwing the economy into a deep recession.
Source: Bloomberg
Technically, the S&P 500 is not as bearish as early 1981 ( 50/200 bear cross in June 1981. Albeit, we are seeing some weekly macd divergences now as then.)