This study examines the value relevance of mandated disclosures by UK firms of the investor-firm share of liabilities of equity-accounted associate and joint venture investees. It does so for the six years following the introduction of FRS 9: Associates and Joint Ventures, which forced a substantial increase in such disclosures by UK firms. Since the increased disclosure requirements were partly motivated by concern that single-line equity accounting concealed the level of group gearing, and in light of previous US results, it is predicted that the mandated investee-liability disclosures have a negative coefficient in a value-relevance regression. The study also examines whether value-relevance regression coefficients on investee-liability disclosures are more negative for joint ventures than for associates and whether they are more negative in the presence of investor-firm guarantees of investee-firm obligations than in the absence of such guarantees. The study reports that the coefficient on all investee-liability disclosures taken together has the predicted negative sign, and is significantly different from zero. It finds little evidence that the negative valuation impact of liability disclosures is stronger for joint venture investees overall than for associate investees overall, or stronger for guarantee cases overall than for non-guarantee cases overall. There is, however, some evidence that the impact for joint venture guarantee cases is stronger than that for joint venture non-guarantee cases and stronger than that for associate guarantee cases.