Options on Alphabet are implying that the stock will move $42 between now and the end of the week — a move of a bit more than 5 percent for the stock. Meanwhile, Amazon options are implying that the stock will move about $53 by Friday — a roughly 6.5 percent move.
Since Google parent Alphabet is a roughly $550 billion company, and Amazon is worth about $390 billion, these moves are $28 billion and $25 billion, respectively.
Of course, the stocks could end up collectively moving much more, or less, than these numbers suggest. However, $53 billion appears to be the market's best guess.
These expected earnings moves are derived from the price of buying both a bullish call option and a bearish put option on the stock. If one expects Alphabet to move more than 5 percent, that trader could express this thesis by buying a call and a put that each have striking prices in line with the stock's current level. Since this trade grants exposure to the stock's upside and downside, and will set the trader back 5 percent of the price of the stock, a move of greater than 5 percent in either direction will make this trade a winner.
Conversely, a trader who thinks that Alphabet will move less than 5 percent can do the opposite, selling both a put and a call.
As a market is made between these two groups, the options prices will converge on consensus expectations of the stock's post-earnings move.