Planned casinos in Anne Arundel County and Baltimore would lose about 10 percent of their slots business if the state authorizes a new venue in Prince George’s County, according to a new analysis by nonpartisan Maryland legislative staff.

A bill, which is the subject of a Maryland Senate hearing Wednesday afternoon, would authorize a new casino in a small swath of Prince George’s that includes both National Harbor and Rosecroft Raceway.

National Harbor (Linda Davidson/THE WASHINGTON POST)

Prince George’s County Executive Rushern L. Baker III (D) recently voiced his strong preference to put the facility at National Harbor, the dining, shopping and conference destination on the Potomac.

According to the analysis, which does not specify a location, a Prince George’s facility could generate about $450 million in slots revenue by 2016. A combined loss of nearly $87 million would be expected at the Anne Arundel and Baltimore locations, it said.

The legislation, sponsored by Sen. Douglas J.J. Peters (D-Prince George’s), attempts to compensate the casino operators by increasing the share of proceeds they are allowed to keep from 33 percent to 40 percent. The bill also allows table games in addition to slot machines.

With those and other changes, the bill could yield an estimated additional $78 million a year for state education programs over what is currently forecast for the state’s five authorized casino locations.

As a host county, Prince George’s would get about $25 million a year as its share of proceeds, according to the analysis. With the expected drop in business, the shares going to Anne Arundel and Baltimore are expected to drop by more than $2 million each.

A casino in Anne Arundel County is expected to open in June at Arundel Mills mall. A state panel is currently weighing a bid from a potential operators of a site in downtown Baltimore, where construction has not begun.