This is the last month to take short and long term capital losses on your stocks for the year 2011. The IRS bases the date of the transaction on the trade date, not the settlement date (however, there are special rules for short sales and for professional traders).
Also, keep in mind the special rules for wash sales:
You cannot deduct losses from sales or trades of stock or securities in a wash sale. A wash sale occurs when you sell or trade stock or securities at a loss and within 30 days before or after the sale you:
*Buy substantially identical stock or securities,
*Acquire substantially identical stock or securities in a fully taxable trade, or
*Acquire a contract or option to buy substantially identical stock or securities.
If you sell stock and your spouse or a corporation you control buys substantially identical stock, you also have a wash sale. If your loss was disallowed because of the wash sale rules, add the disallowed loss to the cost of the new stock or securities. The result is your basis in the new stock or securities. This adjustment postpones the loss deduction until the disposition of the new stock or securities. Your holding period for the new stock or securities begins on the same day as the holding period of the stock or securities sold. Special rules apply to options, futures, and warrants.
This article should not be considered tax or accounting advice. As always, talk to your CPA or tax advisor before taking any action involving tax consequences.