People with a PhD in Economics will be able to add a lot of detail, but what does basic Econ 101 tell us about the value of stocks due to the corporate tax reduction?
The old rate was 35% and the new rate will be 21%. If we assume that the value of a corporation is related to net profit* (after taxes), then the old value was 0.65x and the new value will be 0.79x. The change in the stock market should therefore be 0.79/0.65 or 1.215. The stock market should stabilize at 21.5% higher than before the tax cut.
*The idea is that net profit can be either distributed (dividends or stock buy backs) or invested in the business, which would result in greater future profits.
At the Sky High Café...
2 hours ago