§ 515.010.Undertaking Filed By Plaintiff

The plaintiff's undertaking is what makes the whole provisional remedy fair to a defendant who might ultimately win the case. Subdivision (a) requires the plaintiff to file this undertaking before either a temporary restraining order or a writ of possession can issue. It has to promise that the sureties will answer to the defendant for returning the property if return is ordered, and for paying the defendant any sum recovered against the plaintiff — the kind of damages § 512.120 makes the plaintiff liable for if judgment doesn't go the plaintiff's way.

The amount isn't arbitrary: not less than twice the value of the defendant's interest in the property, and the court can set it higher. That value gets calculated by taking the property's market value and subtracting whatever is still owed on any conditional sales contract or security agreement, along with any liens and encumbrances, and any other factor bearing on the defendant's actual interest.

Subdivision (b) handles the case where the defendant has no interest in the property at all — think of a thief holding stolen goods with no claim of ownership. There, the court waives the plaintiff's undertaking requirement, but it still has to set, in the order for the writ, the amount the defendant's own undertaking would need to satisfy under § 515.020(b) if the defendant later wants to regain possession.