The Section 475(f) Mark-to-Market Election

The Section 475(f) mark-to-market election changes how a qualifying trader accounts for gains and losses. Instead of realising results when positions close, everything is treated as if marked to fair market value at year end, and the results become ordinary income rather than capital. For some traders this is transformative. For others it quietly destroys their single biggest tax advantage. The difference depends almost entirely on what they trade.

What the election changes

The headline benefit is on the loss side. A trader who loses heavily in securities and has no election is stuck with capital losses, deductible against ordinary income only up to a small annual cap, with the rest carried forward, sometimes for many years. With the election those losses are ordinary and can offset other income in the year they occur. For a trader who had a genuinely bad year, this is the difference between relief now and relief eventually.

The wash sale relief is the other real benefit. An active securities trader who repeatedly re-enters the same names can find a large share of their losses disallowed and rolled into the basis of replacement positions, producing a tax bill that looks nothing like their actual economic result. The election removes that problem completely.

The trap for futures traders

This is worth restating because the consequence is easy to miss. The 60/40 rule moves the majority of your futures gain to the lower long-term rate automatically. Ordinary treatment moves all of it to your highest rate. A trader who elects across the board because they read that mark to market is good for active traders can hand back a substantial benefit without ever realising the connection.

The calculus differs by instrument. If you trade securities and lose, the election helps. If you trade Section 1256 contracts and win, extending the election to them hurts. Traders who do both need to think about the two decisions separately rather than as one switch.

The deadline, which is the most common failure

The timing is counterintuitive and it is where most would-be electors come unstuck. For an existing taxpayer, the election for a given tax year must generally be made by the due date of the prior year return, without extensions. In other words the decision has to be made before the year it applies to has really got going, and long before you know how that year will turn out.

You cannot look back at a losing year in the following spring and elect retroactively to convert those losses to ordinary. That is precisely the move the timing rule exists to prevent. New taxpayers and newly formed entities follow different mechanics, which is one of the reasons entity structure comes up in trader tax planning.

Making the election also involves more than one step: a statement filed with the prior year return, and then a change of accounting method reported for the year the election takes effect. Missing the second step after correctly making the first is a real and avoidable failure.

It is hard to undo

The election is not something to try for a year and reassess. Once made it continues automatically, and revoking it requires following a defined IRS procedure rather than simply stopping. A trader who elects during a losing stretch and then becomes consistently profitable may find themselves paying ordinary rates on gains that would otherwise have qualified for better treatment, with no quick way back.

Treat it as a long-term structural decision about how you will be taxed, not as a tactical response to one bad year.

A rough way to think about whether it fits

• You trade securities actively, you take losses, and wash sales are distorting your reported results. The election probably helps.
• You trade Section 1256 contracts and are profitable. Extending the election to them probably hurts, sometimes badly.
• You do not qualify for trader tax status. The election is not available to you at all.
• You are unsure which year the deadline applies to. Speak to a professional now rather than in April, because by April the window for the current year has usually closed.

Sources and Further Reading

For authoritative data and further reading on this topic, refer to IRS and SEC Investor.gov. Always confirm current rules, rates and contract specifications on the official source before you trade.