Only one thing is certain: Family lawyers will profit as more cases head to court.
"In my opinion, a court may take into account a post-separation-date change in the value of a spouse's assets," Mr. Justice Robert Blair wrote.
The decision spared Harold Serra, a multimillionaire owner of a textile business, from having to pay his ex-wife an equalization payment of $4.1-million after his business lost as much as $9-million in value.
That payment, if he had been forced to make it, would have been about twice his current net worth, the court noted. Now, the reduced payment he owes is $900,000.
The decision sets a precedent at a time when stock portfolios and real-estate assets of many estranged couples are losing significant value because of the economic downturn.
Equalization payments in Ontario divorces have long been a source of contention, mainly because there was little anybody could do to have them adjusted.
In Ontario, the value of marital assets is calculated at a fixed time: the date of separation. In other provinces, the valuation date is flexible, and can reflect changes in economic circumstances after the couple parts ways.
Many family lawyers believe the ruling was crucial. "This was one of the top things that the courts had to fix," says Gerry Sadvari, a leading divorce lawyer at McCarthy Tétrault in Toronto.
"Anybody who separated before the summer of 2008 is going to probably be affected by the downturn, and the equalization will be higher than it would have been if calculated afterward. I and [other lawyers] have several cases where the equalization payment is greater than the remaining net worth of the individual."
But the fight for fairness won't be easy or straightforward.
A reprieve from paying a previously calculated equalization payment only comes if Ontario courts find the change in asset value "unconscionable," a term that is not the same as unfair and means it has to "be shocking to the conscience of the court," Mr. Sadvari explains.
"So, if your portfolio is down by 20 per cent, that's not even close to the test. If it's down 50 per cent that may be enough, but it will depend on other factors. If it's down 90 per cent, that's probably enough. Justice Blair was careful to say that a reduction in the value of a portfolio by itself may not qualify. ... [But] the court didn't define what kind of decline."
The decision "leaves ambiguity," says Victoria Smith, a collaborative divorce lawyer in Toronto.
"Until there's clarification or further precedent, or until the legislation is amended, it will be difficult to know where you draw the line. It will open litigation, without a doubt," she says.
Another way to put it? Lawyers, start your clocks.