Choice Overlap and Reputation Feedback in Creator-Brand Matching

Content platforms create reputation feedback when past bookings improve creators' rankings for future paid promotions. We study how the alternatives available to different brands shape the stability of this feedback and creators' access to bookings. At any positive fixed point, a normalized choice-overlap matrix determines the local stability threshold of the mean booking dynamics. Markets with identical creator positions and effective choice can lie on opposite sides of this threshold. A separate reinforcement threshold governs attraction toward monopoly allocations, allowing stable interior and monopoly states to coexist. We derive a sharp constraint linking effective choice to admissible reinforcement, so choice expansion and reputation weighting must be evaluated jointly. Finite-sample spectral bounds support policy selection under explicit calibration assumptions. Uniform exploration removes boundary equilibria and provides a finite-window access bound, although small exploration shares can still sustain concentrated interior states. Controlled simulations test the stability thresholds, spectral bounds, and event-level access. Among booked creators, offline estimates associate a one-standard-deviation increase in booking evenness with a 7.13% higher audience-tier advancement probability relative to the sample mean; a reported 60-day online comparison shows a 3.4% increase in gross promotion transaction value (GMV). The framework distinguishes creator variety, brand-facing choice, and sustained access as separate design objectives.