Increase in value of assets after divorce is filed

Just got this question a minute ago, and, for some reason, it's one of my favorite subject areas:

Is your net value of marital assets determined once you file a petition for divorce? For example, let's say a stock is worth $10,000 when you file for divorce and the next day the stock is worth $20,000. If the stock is in my name only, how much does my spouse get?

Answer:

Very good question. The simple answer is: it's up to the judge. Sometimes assets are valued at the time of filing of the petition, sometimes they are valued at the time of trial. The appellate courts say that a judge should look at whether the increase in value of the asset is due to active or passive activity. If the increase is due to passive activity, the asset is valued at the time of trial. If the increase is passive, the asset is valued at the time of the trial.

Here's why:

If the asset increases in value between the time of filing and the time of trial through no activity of a spouse, it's only fair to split the asset at the time of the trial; both parties should get the benefit of the increase.

On the other hand, let's say the husband stays in the marital home after the divorce is filed. Between the time of filing and the time of trial, the husband adds a room on to the house. Obviously, the increase in value of the house is due to the husband's active work. Therefore, it's only fair that he receive the value of the increase. The house would be given the value that it had when the divorce case was filed, which was before the husband added the room. The husband would receive all the value of the added room.

So, if stock is worth $10,000 at the time of filing, and increases to $20,000 the next day, we have passive increase, and the judge should give both parties the benefit of the increase. The $20,000 would be split.