The targeted boycotting of businesses involved in Israel's occupation of the Palestinian Territories is legitimate
The Norwegian government's divestment from Elbit Systems is an entirely appropriate response to Elbit's business involvement with the occupation of the West Bank. Despite the howls of protest from Israeli officials, the Norwegians' decision is a principled stand, which bears the closest of scrutiny, especially when viewed in the context of previous decisions by the country's council of ethics regarding state investments.
Claims that Elbit is being unfairly singled out due to its being an Israeli company ring hollow given that Norway's public pension fund also refuses to invest in 30 other firms' shares, including Boeing, Wal-Mart and British Aerospace. Elbit's role in constructing and maintaining Israel's separation barrier – deemed illegal in its entirety by the international court of justice (ICJ), and in part by the Israeli supreme court – means that any fund interested in maintaining an ethical stance towards investment ought to steer well clear of Elbit's stock.
While an indiscriminate boycott of all Israeli produce is both wrong-headed and counterproductive, that does not mean specific sanctions ought to be proscribed in cases where the companies involved are clearly making money from piling misery on the Palestinians. It has been pointed out that Norway's fund managers could go even further than simply scratching their investment in Elbit, given that almost two-thirds of the 41 Israeli companies in which the Norwegian pension fund holds stock "have significant economic interests in the continued Israeli occupation", according to the Coalition of Women for Peace.
Read more @ The Guardian's Comment Is Free
Some good info in that article, even mentioning situations where pressure has worked.
More importantly, the link at the end of the quoted bit - http://www.whoprofits.org/ - is a good resource to get details of the activities of companies making sure you are boycotting the right ones.
"For too long, we have been a passively tolerant society, saying to our citizens 'as long as you obey the law, we will leave you alone'" - David Cameron, UK Prime Minister. 13 May 2015.