Q:

Selling high, pay capital gains, re-purchase later

I'm trying to come up with a formula that tells me how far a stock must fall from a selling point before I re-purchase it with the assumption it will regain the selling price. In other words, if I sell stock and pay capital gains, at what point could I re-buy the stock to offset taxes paid with the following assumptions:
ASSUMPTIONS

Long term capital gain.
0.15 tax rate.
Cost basis/share < selling price/share
Assumes stock will go down.
Assumes stock will recover to selling price.

A:

Ignoring brokerage fees and the wash-sale rule (both of which are hazardous to your health), and since the 15% LTCG tax is only on the gain, the stock would have to drop 15% of the gain in price since you originally purchased it.
(SALEPRICE - PURCHPRICE) * .15 == Amount it would have to drop

