Developer Milt Peterson will put $400,000 into an effort to expand gambling in Maryland, the first non-casino interest to write a check.
Peterson hopes to partner with gambling giant MGM Resorts International to build a resort-casino on the Potomac River. But first Maryland voters need to approve a referendum question in November that would authorize a sixth casino and table games all gambling locations.
MGM has already put $5.4 million behind and effort to convince Marylanders to vote yes.
Penn National Gaming is funding an effort to oppose the ballot measure.
The new donation will bring the total spent on both sides to $11.3 million.