Salem Media Group on Monday announced it has acquired finance newsletter Retirement Watch, a website that offers advice and resources to retirees. This is the latest in a string of finance and investment digital platforms that the Camarillo multimedia company has purchased in the past year. Salem Media, known for its Christian and politically conservative radio properties, acquired Washington, D.C.-based Eagle Publishing in January 2014 and has since added to its portfolio of investment newsletters and trading services with roughly a dozen sites including DividendInvestor.com and EagleDailyInvestor.com. Retirement Watch was launched in 2008 and is operated by Robert L. Carlson, author of “Invest Like a Fox, Not Like a Hedgehog” and “The New Rules of Retirement.” “I am thrilled to add Retirement Watch to our mix of products. Our current products have focused more directly on portfolio advice, so adding a resource aimed at all aspects of retirement planning is a perfect complement to our other offerings,” Roger Michalski, vice president and publisher of Eagle, said in a statement. Shares closed up 35 cents or 6 percent to $6.38 on the Nasdaq.