The Massachusetts Taxpayers Foundation published a new report on Thursday describing the financial future of the state’s largest public transit agency as “unequivocal and unsettling.”

Despite the infusion of $2 billion in federal stimulus funds during the COVID-19 pandemic to offset declines in ridership, the nonprofit research group said that by the spring of 2023 the MBTA could be looking at an operating budget gap of between $200 million and $400 million for the next fiscal year.

By fiscal year 2025, the gap grows to $450 million and by fiscal year 2026 it reaches $500 million, requiring substantial fare increases or service cuts and layoffs, according to the report.

The authors of the study described the predicament facing public officials, including the next governor, as a “Hobbesian choice” between raising revenue or accepting service cuts “that will exacerbate inequities and derail the Greater Boston economy.”