** Shares of Lockheed Martin LMT.N gain 1.8% to $518.76

** Citigroup raises to "buy" from "neutral"; lifts PT to $582 from $571, representing an upside of about 12% to stock's current trading price

** Brokerage says many defense stocks registered one of their worst quarterly declines, and LMT historically bounces back "consistently and sharply" after such pullbacks

** Says cheap valuation, improving fundamentals, exposure to fast-growing themes through its Missiles and Fire Control (MFC)segment present attractive risk

** Valuation for aftermarket stocks, companies that provide services and products after the original sale, is close to multi-year lows, and positive trends could lead to large beats on results - Citi

** Average rating of 24 analysts is "hold", with median PT at $607 - LSEG-compiled data

** Including session's moves, LMT up about 7% YTD vs a near 9% growth in the S&P 500 Aerospace & Defense sub-index .SPLRCAERO