Merck & Co., Inc ( MRK) has been named a Top 25 Socially Responsible Dividend Stock by Dividend Channel, signifying a stock with above-average ''DividendRank'' statistics including a strong 3.5% yield, as well as being recognized by prominent asset managers as being a socially responsible investment, through analysis of social and environmental criteria. Environmental criteria include considerations like the environmental impact of the company's products and services, as well as the company's efficiency in terms of its use of energy and resources. Social criteria include elements such as human rights, child labor, corporate diversity, and the company's impact on society — for instance, taken into consideration would be business activities tied to weapons, gambling, tobacco, and alcohol.According to the ETF Finder at ETF Channel, Merck & Co., Inc is a member of both the iShares MSCI USA ESG Select Social Index Fund ETF (KLD), making up 1.63% of the underlying holdings of the fund, as well as the iShares MSCI KLD 400 Social Index Fund ETF (DSI), where MRK makes up 2.25% of the underlying holdings of the fund. The annualized dividend paid by Merck & Co., Inc is $1.76/share, currently paid in quarterly installments, and its most recent dividend ex-date was on 12/12/2013. Below is a long-term dividend history chart for MRK, which the DividendRank report stressed as being of key importance. Indeed, studying a company's past dividend history can be of good help in judging whether the most recent dividend is likely to continue.