A 1-to-1 Stock exchange implies that there will be little change in the stock price once the merger is done. The company is roughly doubling in size (per presentations) and there will roughly be double the number of shares. Hence no real change in stock price. It is not an IPO, so there will be no announcement of share price pre-opening of the new, combined company. It will be what the market will bear, but should be little changed from current price (at the time of the merger). There may be a little movement upwards from the deal closing successfully, which removes uncertainty.