Quote from freewilly:
Hi,
I had pretty big gain on trading in 2009. I just heard that I can not wait to file tax return till April 15th, otherwise I will get big penalty.
.....
freewilly
It depends on when the "big gain" was made on trading in 2009. If you made those gains in Q4 2009, you still have time to file estimated tax without penalty. Deadline for Q4 2009 estimated tax is Jan 15, 2010.
If your gains were throughout the year (Q1, Q2, Q3), you are supposed to make estimated payments throughout 2009. If it is the case, still, you should make your estimated tax payment before Jan 15, 2010 to avoid further interests (penalty).
Don't quote me on this but I think the penalty (interest) is something like 1% per month for the amount of tax owed. I think. The IRS publications have the exact figures.
You have up to April 15, 2010 to file your 2009 tax return (and August 15, 2010 if you apply for an extension). You just can't owe them taxes without penalty.
Use form 1040 ES for your estimated tax payments.
And don't forget the state tax estimated tax (if applicable) too.