We will present two broad overview examples.  One will exhibit the tax benefits of the MTM election whereas the second will show the potential detrimental impact of the election.

Note:  These are two separate examples shown using the same security (SPX) so each example is a stand-alone scenario, not cumulative.

Example 1:  Trader purchases 100 shares of SPX on 3/10/2008

Example 2:  Trader purchases 100 shares of SPX on 4/21/2009

Example 3:  Continuing Example 1 with a subsequent sale

Example 4:  Continuing Example 2 with a subsequent sale

Assumption:  Trader made a timely and effective MTM election prior to tax year 2008.

This example also uses a stock index instead of an ETF or single stock.  Thus the gain or loss when trading the index itself is reported on Form 4797, Part II while gain or loss on options on the index is reported on Form 6781.  If this had been an ETF or single stock, it would also be reported on Form 4787, Part II.

Chart of SPX for 2008 and 2009

Conclusion

As you can see, there is a tax benefit when a loss can be recognized.  Additionally, this loss may be carried back for three years to prior tax periods and offset any prior year capital gains.

However, there is the potential for additional tax liability based on the deemed sale at a higher price.  If you do not have the funds to pay the tax you may need to sell a position you do not want to sell as in Example 2 & 4.

Basis Adjustment

In Example 1, the new basis in the shares is adjusted for the loss recognized.  Therefore, new basis per share is $903.25 and the holding period is short-term (Example 3).

Similarly, in Example 2, new basis is adjusted for the gain recognized.  Thus, the new basis per share is $1,115.10 and the holding period is again, short-term (Example 4).

Note that in the following examples, a negative amount is cash out or a debit to one’s brokerage account and a positive amount is cash in or a credit.