When does the US tax year ends?

I was told that one can sell a stock before december
31 starting from now (12/27/07) and still be able not
to pay tax on that selling until next year.Is that true?
Thanks.

Appreciate all the responses and the
reason for what I heard might be as
someone here suggested the use of
settlement date -which occurs 3 business
days after the sale- with the selling date
which is incorrect.

Anyway,after posting the question I found
about publication 538 which seems to me that it allows any person to have establish his own accounting period if he
wishes.
Just wanted to help back and to see if
anyone want to comment on that.

It ends on 12/31/07

The tax year ends on December 31 at midnight, unles you have previously declared a different tax year (businesses). As an individual you gotta report it on 2007 taxes (due 2008) if you sell it this year. If you have held it long enough, you may qualify for reduced rates as a capieal gain as opposed to straight income.

The IRS instructions for schedule D say to use the trade date for the date of sale. The trade date is the date you commit to the sale; the settlement date is often 5-6 days later and is the actual date the broker takes your money.

(At least one person here has told people it's the settlement date...which is wrong.)

Consequently, if you do not want to pay taxes, wait until 1/2 to sell.

The tax year ends 12/31, if you sell stock during the year you have to report it on Sch. D. As someone else mentioned for tax purposes you use the trade date, not the settlement date on your return. So, if you sell before 12/31 the sale is taxable on your 2007 taxes.

i dont know,i dont pay tax

suppose to be april 15 then you can get extentions that is if you owe taxes