Defense spending is the amount the sovereign of a country invests in weapons, weapon systems, and soldiers.
It is impossible (today) to get perfect exposure to increases in defense spending, because not all beneficiaries of increases are private companies - i.e., increases in defense spending could be used for increases in soldiers' salaries. (However, PMCs are becoming more widespread at it is not impossible to imagine a time when all soldiers are private contractors.)
Major defense companies include Lockheed Martin (LMT) , Raytheon Company (RTN) and Boeing Company (BA). Defense companies that focus on software include SAIC (SAI). One OTCBB listed security within the defense sector is Sector 10 (SECT).
iShares ETF (ITA)
Trends in US Spending