Paper
A stricter proxy core lowers the rate, but it does not make the backlog disappear or confine it to one kind of sponsor.
Which sponsors still dominate the strict U.S.-nexus CT.gov core once attention shifts from sector averages to named repeaters? We analysed the 58,598-study strict U.S.-nexus drug-biological-device proxy extracted from the March 29, 2026 full-registry snapshot. We ranked strict-core sponsors with at least 50 studies and compared sponsor classes and condition families on missing-results and black-box stock inside that regulated-looking subset. National Cancer Institute carried the largest strict-core no-results stock at 361 studies, followed by Mayo Clinic at 204, MD Anderson at 198, and Sanofi at 186. OTHER and INDUSTRY remained close on strict-core stock at 8,824 and 7,983 studies, but NETWORK had the highest large-class no-results rate at 48.8 percent. The strict-core backlog therefore remains institutionally distributed across government-linked, academic, and industry sponsors rather than collapsing into one regulated archetype. These repeaters sit inside a conservative proxy core and should not be read as formal ACT or FDAAA legal determinations for specific studies or sponsors or enforcement.