Is Shorting BOIL Every Winter Really Free Money?

Shorting BOIL every winter is a popular idea. BOIL is a 2x leveraged natural gas ETF that suffers from decay, and natural gas demand typically peaks during the colder months. The strategy calls for shorting in December and covering in spring to capture both seasonal weakness and a full year of leverage decay in just a few months. We tested this approach over fourteen winters using split-adjusted data. The edge exists, but it is far from easy to capture.

First, BOIL really is a melting ice cube

Start with the thing that makes the whole idea plausible. Since it launched in 2011, BOIL has lost effectively 100% of its value on a split-adjusted basis. Reverse split after reverse split, it has ground toward zero. Two times daily leverage on one of the most volatile commodities there is, plus the cost of rolling natural gas futures, is a recipe for relentless decay. Shorting it at a random moment and holding three months made money 69% of the time, and shorting it for a full year averaged +46% (median +60%), profitable in 11 of 14 years. So shorting BOIL is, on average, like shorting an ice cube on a warm day. That part is true any time of year.

Winter is the worst season for it

The seasonal claim holds up too. Sorted by calendar month, BOIL's two worst months by a wide margin are the winter months.

Month	Average BOIL return	Shorting it earned
December	-19%	+19%
February	-12%	+12%
October	-5%	+5%
April	+5%	-5%
August	+5%	-5%

December and February alone gave back nearly a third of BOIL's value on average. The winter short is not arbitrary, it lands right on the two months where the decay is fiercest. (Note that the deep-winter month, January, is the weak link at roughly flat, because January is when cold snaps actually hit. More on that in a moment.)

So how good is the winter short? On the median, very

	Dec-Feb winter short	A random 3-month short	Short BOIL all year
Average return	+31%	+10%	+46%
Median return	+49%	+17%	+60%
Win rate	87%	69%	79%

The Dec-Feb short won 13 of the last 15 winters, with a median return of +49% in three months. That is roughly a full year's worth of decay earned in one quarter, and about three times what you would have made shorting a random quarter. If it ended here it would be free money, but it does not end here.

The catch: the one winter in seven that ends the game

Each bar is the three-month winter (December to February) short return for that year. Green is a profitable short; red is a loss. Two winters, 2014 and 2025, gave back years of gains.

The two losing winters are not bad luck, they will keep showing up. 2014 was the polar vortex. 2025 was a hard cold snap. Both sent natural gas vertical, and BOIL, at two times leverage, doubled the move and rocketed up, handing the shorts a 45% and a 70% loss. Widen the window slightly to November through March and a trader would have lost 130% in the winter of 2025. You are, after all, shorting a leveraged long-volatility product into the exact season it is built to explode. The same leverage that melts BOIL in a mild winter detonates it in a cold one.

And a short that loses more than 100% is not a drawdown you recover from. Any one cold winter is terminal, and you cannot know in advance which winter it will be.