When one spouse (usually the high wage earner) tries to or has already hidden a lot of the financial transactions that have occurred so the other spouse has no idea that it happened; if one does not know about it, one normally does not try to "divide" it because one doesn't know anything about its existence.
If the spouse that never divulged the asset never lists the asset or assets, and the other spouse finds out afterward, the Family Law Code has specific laws for how long a person has to try and fix the error. Waiting too long may possibly cause a complete loss. This is why it is important to understand one's rights in divorce, and attorney has seen many litigants try to save $1,000 in fees by not using any discovery, but end up losing far more than that when it was too late to fix or change what happened.
Many of the forms used in divorces are set up so that the disclosure of financial related items are set forth for division. for example, Judicial Council Form FL-140 [declaration of disclosure]
and then FL-145 [form interrogatories].....http://www.courts.ca.gov/documents/fl145.pdf
These basic inquiries and answers may lead to the discovery of assets that one spouse knows nothing about at all. While this will not happen in all cases, it has become fairly common for attorney to see pro se litigants who are unaware that the pensions (which may be split in divorce) are not set up in the same format, and may depend upon the employer, longevity, type of plan and much more....in some cases, an actuarial accounting should be performed. Pension plans may need to be joined. There can be quite a bit of variance in exactly what needs to be done, as it depends on the plan and how it is set up.
Attorney has also seen cases where spouses believed that they had funds set aside for themselves and found out later that the other spouse had liquidated their accounts without them knowing it. Also in bankruptcy, various plans/pensions can be treated differently depending on the type and category and if there are no exemptions for it, one's funds can be at risk of loss. Filing bankruptcy usually requires pre-planning so that no errant steps are taken, but legal choices can help avoid loss without being illegal. Tax refunds are often lost due to no knowledge of exemptions/or timing issues.
When non disclosure takes place, and the spouse who was unaware of it discovers it, this can create additional litigation because it often takes litigation in order to have the spouse (who didn't know about the assets)-- rectify the situation. For divorces that involve higher stakes, such as valuation of a professional business, or a large business which the other spouse knows very little about-- these can be problematic due to the nature of business records.
Or, it is possible that one spouse is consistently hiding income and cash and claiming only 1/10th of what is really coming in. These are difficult situations but not impossible. Diligence, time and dedication to uncovering the facts is required and when facts are shown proving that one spouse has used fabrication, the court can punish the offending party. Especially in spousal support, most courts heavily frown on fabrication of income, and in bankruptcy, legal fees used to obtain spousal support are not dischargeable, and child support is usually never dischargeable.
If you have a divorce case and believe that the other spouse has hidden assets or misrepresented where the money actually went, you should consult several attorneys. There may be a difference of opinion on how to approach the issues.