The STAGE Act creates a new federal grant program administered by the Secretary of Commerce to provide funding directly to professional nonprofit theaters across the country. Eligible organizations must be tax-exempt nonprofits with at least three years of programming history that pay performers at prevailing wage rates and have not violated major labor and employment laws. The grants can be used for payroll, operating expenses, facility improvements, workforce development, and other costs that support long-term viability and employment, with individual grants capped at either 20 percent of an organization's annual expenditures or $16 million, whichever is less. The bill authorizes $1 billion annually for fiscal years 2024 through 2028, with at least half of those funds reserved for theaters that primarily produce theater productions, and requires a study on sustaining the broader nonprofit arts sector to be completed within two years.