The US stock market is set to modernize its trading cycles by reducing the settlement period for stock trades from two days to one day. This change, effective from tomorrow, marks a significant shift in the financial industry, bringing the market's speed in line with what it was about a hundred years ago. The move comes under new rules established by the Securities and Exchange Commission (SEC) and is anticipated to enhance the efficiency and responsiveness of the market. The new settlement cycle is referred to as T+1.