Bloomberg reported the US labor market has little room to tighten, according to a new study from the Federal Reserve Bank of San Francisco that examines trends in the number of Americans who are either working or looking for jobs. “Our estimates indicate that the aggregate labor force participation rate is at its trend as of 2018,” the regional Fed bank concluded in an Economic Letter published Monday. “Combined with the low unemployment rate, this argues that the US labor market is operating at or beyond its full potential.”