By Doc Louallen

GATX Corporation said it exercised the first of its call options to increase its interest in GABX Leasing LLC to about 33.5% from 30%.

The move came through buying an interest in GABX Leasing Holding LLC, a holding entity for the joint venture. The remaining stake is held by an affiliate of Brookfield Infrastructure Partners and its institutional partners.

Under a 2026 agreement, GATX holds a series of call options that, if exercised in full, would let it acquire all of the joint venture over time.

Following the latest step, the holding company's LLC agreement was amended to add GATX as a member and give it joint approval rights over certain major actions. Which includes, amendments, equity issuances, new debt, capital calls and major transactions. Brookfield will remain the managing member unless and until GATX owns all the outstanding units.

Write to Doc Louallen at Doc.Louallen@wsj.com