Is this consider Long Term Capital Gain?

I purchased 300 Shares of MasterCard (MA) back in Aug 2006 and Sold it in December of 2007 which should be consider long term gain but I also purchased another 300 shares of MasterCard on Sept 2006 and sold it on December 2006 which is consider short term gain. Could I still consider the purchase back in Aug long term? Thanks for any help with clearing this out.

Your profit from the December, 2007 sale is definitely long term gain, but it's very important for you to know the cost basis of the shares you are selling. That was determined by the reporting method you used on your 2006 tax return for the sale of 300 shares in December, 2006. Your question indicates that you believe the December, 2006 sale was of the shares you bought in September, 2006. That is possible, but it is not the default method used by the IRS. The default is "FIFO" or "first in, first out". If you didn't make any effort to use an alternate method of calculating cost basis, the IRS will assume that the 300 shares purchased in August, 2006 were the ones sold in December, 2006 and that the 300 shares sold in December, 2007 were the ones bought in September, 2006.

To get the shares sold in the order that you indicate, you would have had to use the "specific id" method. You would have had to instruct your broker at the time of the December, 2006 sale to sell the 300 shares purchased in September. If you didn't do this, you can't use the "specific id" method.

There are four allowable ways to calculate cost basis, which would most likely lead to completely different tax bills for your MA profits.

As you can see, this is a complicated issue with plenty of potential traps for the unwary.

Yes, you can consider the first 300 shares as a long term gain. You report them separately just like they appear on your brokerage statement