Stock, mutual fund and ETF prices have bounced around lately. If you make what turns out to be an ill-fated investment in a taxable brokerage firm account, the good news is that you may be able to harvest a tax-saving capital loss by selling the loser security. However, for federal income tax purposes, the wash sale rule could disallow your hoped-for tax loss. Rule basics A loss from selling stock or mutual fund shares is disallowed if, within the 61-day period beginning 30 days before the date of the loss sale and ending 30 days after that date, you buy substantially identical securities. The theory behind the wash sale rule is that the loss from selling securities and acquiring substantially identical securities within the 61-day window adds up...