Shares of Woodland Hills-based online wagering company Youbet.com Inc. jumped 13 percent on Thursday after it announced a deal to offer live online video and wagering for horse races at 10 U.S. racetracks.

Youbet, which already offers races at Santa Anita Park in Arcadia and Golden Gate Fields in the Bay Area, expanded its relationship with racetrack owner Magna Entertainment Corp. to include properties outside of California.

The new agreement covers Gulfstream Park in Miami, Laurel Park and Pimlico Race Course in Maryland and seven other Magna venues.

In midday trading, Youbet shares rose 51 cents to $4.42 each. Youbet’s 2005 season in California will launch on Dec. 26 when it carries the opening races at Santa Anita Park.