Now is the time when investors start thinking about the tax side of their investments. Invariably, you'll probably be tempted to sell some losers before the end of the year in order to offset some of your gains.

If you do some selling, make sure you don't run afoul of the "wash sale" rules. Here are some things you need to know:

• Wash sale rules prohibit you from buying the same or "substantially identical" securities sooner than 31 days before or after you sell your losing investment. For example, if you sell a security to book a loss and buy back the stock sooner than 31 days, you may lose, or at the very least postpone, the tax benefit. Or, let's say you own 100 shares of Lucent. If you buy another 100 shares of Lucent and immediately sell 100 shares (in order to book a loss), you will lose the tax deduction. In this case, you must wait at least 31 days before selling.
  
  
• The 31-day waiting period applies to calendar days and may straddle tax years.
  
  
• You may not claim a loss deduction if you sell stock and then your spouse or another "related person" buys substantially identical stock.
  
  
• Be careful if you buy stocks or mutual funds with reinvested dividends or automatic monthly investment. Such buying could affect your ability to book a loss deduction if the purchase occurs sooner than 31 days after the sale. You may be able to suspend a reinvestment period or monthly purchase program by contacting the broker, company, or mutual fund.