Equity research primarily means to provide investors with detailed financial analysis for historical and projected data, performing ratio analysis and recommendations on whether to buy, hold, or sell a particular investment.
Divestment involves eliminating (sell/close/spin-off) a portion of a business, either the less-profitable division or for the purpose of the liquidation.
Investment is made with a goal to identify companies whose products or services can synergistically integrate with their existing product line to create incremental, long-term shareholder value.