Counties in Texas, New York and Florida dominated a list of hidden gems in the rental real estate market, a study released Thursday said. Online real estate firm RealtyTrac and rental data firm RentRange said they evaluated 450 counties nationwide with populations of 100,000 or more and unemployment rates of 7.5 percent or lower. They then looked for the top 25 markets that had the highest gross rental yields for residential rental properties in areas where institutional investors accounted for 5 percent or less of all residential sales in a three-month period ending in July. Then they analyzed data, but limited their scrutiny to single family homes with three bedrooms, so they knew they were comparing apples to apples. If institutional sales constituted a small percentage of all sales, that suggested the county\'s opportunities as a rental market were still undiscovered by the larger players, leaving opportunities for smaller companies with 10 properties or less under their management, RealtyTrac said. They also looked for counties with lower than average unemployment rates, which suggested there were potential tenants with jobs in the area. Wichita County, Texas, which made the list, has a median market value for properties at $84,000, investor sales of 4.5 percent and an unemployment rate of 6.8 percent. The gross yield for properties there topped the list at 13.4 percent. Gross yield is determined by dividing the gross annual rental income by the purchase price or the market value of a property. Other hidden gems included Lubbock County, Texas, with a gross yield of 11.8 percent, Onondaga County, N.Y., with a gross yield of 10.9 percent and Canadian County, Okla., with a gross yield of 10.8 percent. The top 10 included Tompkins County, N.Y., Williamson County, Texas, Monroe County, N.Y., Davidson County, Tenn., Alachua County, Fla., and Schenectady County, N.Y. The top 25 includes three counties from Texas, four from New York, and three from Florida, RealtyTrac said.