OPG’s Preferred Providers We are proud to present the talented organizations that help OPG tick! Hirtle Callaghan: Holding ourselves accountable to the highest standard, we build complete, custom-designed investment solutions that will open possibilities for greater cures, more education, smoother retirement and future generations. Arc Marketing: Arc is a micro digital marketing agency that tells your brand’s story to the people who it will impact the most. At Arc we blend storytelling into digital strategy, because there is no single lever you pull. It all has to work together. Xponent21: By leveraging designed experiences, innovative marketing strategies, and tools developed to help you meet your business goals, we help attract and convert your ideal customers in order to drive your company’s growth and build a loyal fanbase.