投资学研究如何把个人、机构的有限资源分配到诸如股票、国债、不动产等（金融）资产上，以获得合理的现金流量和风险-收益特征。

其核心内容就是以效用最大化准则为指导，获得个人财富配置的最优均衡解。

To invest is to allocate money (or sometimes another resource, such as time) in the expectation of some benefit in the future.

In finance, the expected future benefit from investment is a return. The return may consist of capital gain and/or investment income, including dividends, interest, rental income etc.