When a company makes an all stock buyout offer does the ratio move with the market or is the price fixed as of the day of the offer?

Example: Tesla offered to buy Solar City. Text from offer is below. So is the ratio of exchange what matters? In other words as Tesla share goes up, so should SCTY if the deal goes through? Or does the offer remain at a value of 26.50 to 28.50.

"We are pleased to submit to you and the SolarCity board of directors a proposal to acquire all of the outstanding shares of common stock of SolarCity in exchange for Tesla common shares. Subject to completing due diligence, we propose an exchange ratio of 0.122x to 0.131x shares of Tesla common stock for each share of SolarCity common stock. This proposal represents a value of $26.50 to $28.50 per share, or a premium of approximately 21% to 30% over the closing price of SolarCity’s shares, based on today’s closing price of SolarCity’s shares and the 5-day volume weighted average price of Tesla shares."

Submitted July 28, 2016 at 09:28AM by VaguelyRobot http://ift.tt/2aMNsXJ