Discovery regarding expert witnesses is governed by Missouri’s Supreme Court Rules, Rule 56.01. MO. ANN. STAT. § 56.01 (West 2017). This rule allows discovery into the hourly fee the expert witness charges for its services. Id. However, if financial information is being used to impeach the expert witness, the requests for discovery “must be no more intrusive than necessary and should not be unduly burdensome or require production of confidential information.” State ex rel. Pooker ex rel. Pooker v. Kramer, 216 S.W.3d 670 (Mo. 2007). Further, inquiries into financial information that requires disclosure of personal private material that is not related to income as an expert is not discoverable. State ex rel. Lichtor v. Clark, 845 S.W.2d 55 (Mo. Ct. App. 1992).
