Lehman Brothers upgraded Boyd Gaming ( BYD

) to strong buy from buy.

Analyst Joyce Minor says shares declined 7.5% on Thursday and the stock now is down 22% from its close on May 31, before Illinois voted to increase gaming taxes. While concerns linger as nearby Indiana considers an increase in its gaming taxes, she thinks the 22% decline in Boyd share more than fully discounts both events.

Additionally, once the Indiana tax question is resolved, Minor thinks investors will look to Boyd's bright future. She believes current weakness represents a nice buying opportunity ahead of major property openings, which are viewed typically as a catalyst. Boyd shares are the cheapest in the gaming group.