The delta of this trade remains negative throughout the stock’s descent to
$75. Assuming the $5 drop occurs in one day, a delta averaging around
−0.36 means about a 1.80 profit, or $180 per spread, for the $5 move (0.36
times $5 times 100). This is still a far cry from the spread’s $3.70 potential
profit. Although the stock is at $75, the maximum profit potential has yet to
be reached, and it won’t be until expiration. How does the rest of the profit
materialize? Time decay.
The price the trader wants the stock to reach is $75, but the assumption
here is that the move happens very fast. The trade went from being a long-
volatility play—long gamma and vega—to a short-vol play: short gamma
and vega. The trader wanted movement when the stock was at $80 and
wants no movement when the stock is at $75. When the trade changes
characteristics by moving from one strike to another, the trader has to
reconsider the stock’s outlook. The question is: if I didn’t have this position
on, would I want it now?
The trader has a choice to make: take the $180 profit—which represents a
138 percent profit on the 1.30 debit—or wait for theta to do its thing. The
trader looking for a retracement would likely be inclined to take a profit on
the trade. Nobody ever went broke taking a profit. But if the trader thinks
the stock will sit tight for the remaining time until expiration, he will be
happy with this income-generating position.
Although the trade in the last, overly simplistic example did not reap its
full at-expiration potential, it was by no means a bad trade. Holding the
spread until expiration is not likely to be part of a trader’s plan. Buying the
80 put outright may be a better play if the trader is expecting a fast move. It
would have a bigger delta than the spread. Debit and credit spreads can be
used as either income generators or as delta plays. When they’re used as
delta plays, however, time must be factored in.