It's a method of invoking the "loser pays" rule in Florida. It can also be used in some types of family law actions (I saw you posted under family law), though it isn't common since there are other ways of invoking "loser pays" in family law cases. A "57.105" claim asserts that all or part of a lawsuit has no legal and/or factual basis and demands that the lawsuit or claim be dropped within 21 days after receipt of the notice or the loser and, in certain circumstances, the loser's law firm, must pay the attorneys' fees and costs of the winning side.
The statute has some very technical requirement, and a 57.105 claim should only be filed by a lawyer or with careful consultation with a lawyer. One side may not claim attorneys' fees and costs against the losing side if that side does not actually have an attorney.
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It is a motion for sanctions, should be used wisely, and there are procedural steps to utilizing it that must be followed and are outlined in the statute itself. You should really contact an attorney if you are thinking of just filing one of these.
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