What's really fun is, you bought a stock a long time ago, it spun off some other companies which got acquired by yet other companies, such that you now own seve

What's really fun is, you bought a stock a long time ago, it spun off some other companies which got acquired by yet other companies, such that you now own several stocks, all attributable to the purchase of that one stock a long time ago. Now you sell some of the resulting stocks, and you need to compute your basis in order to figure the taxable capital gain or loss. This entails looking up the ratios from the various spin-off / acquisition events to determine how much of the original cost to allocate to the sold shares.