投资组合用英语怎么?什么是纯因素投资组合?

　　股票投资组合，是指投资者在进行股票投资时，根据各种股票的风险程度、获利能力等方面的因素，按照一定的规律和原则进行股票的选择、搭配以降低投资风险的一种方法。其理论依据就是股市内各类股票的涨跌一般不是同步的，总是有涨有跌，此起彼伏。因此，当在一种股票上的投资可能因其价格的暂时跌落而不能盈利时，还可以在另外一些有涨势的股票上获得一定的收益，从而可以达到回避风险的目的。应当明确的是，这一种方法只适用于资金投入量较大的投资者。
　　股票投资管理是资产管理的重要组成部分之一。股票投资组合管理的目标就是实现效用最大化，即使股票投资组合的风险和收益特征能够给投资者带来最大的满足。因此，构建股票投资组合的原因有二：一是为降低证券投资风险；二是为实现证券投资收益最大化。
　　组合管理是一种区别于个别资产管理的投资管理理念。组合管理理论最早由马柯威茨于1952年系统地提出，他开创了对投资进行整体管理的先河。目前，在西方国家大约有1/3的投资管理者利用数量化方法进行组合管理。构建投资组合并分析其特性是职业投资组合经理的基本活动。在构建投资组合过程中，就是要通过证券的多样化，使由少量证券造成的不利影响最小化。
　　一、分散风险
　　股票与其他任何金融产品一样，都是有风险的。所谓风险就是指预期投资收益的不确定性。我们常常会用篮子装鸡蛋的例子来说明分散风险的重要性。如果我们把鸡蛋放在一个篮子里，万一这个篮子不小心掉在地上，那么所有的鸡蛋都可能被摔碎；而如果我们把鸡蛋分散在不同的篮子里，那么一个篮子掉了不会影响其他篮子里的鸡蛋。资产组合理论表明，证券组合的风险随着组合所包含的证券数量的增加而降低，资产间关联性低的多元化证券组合可以有效地降低个别风险。
　　我们一般用股票投资收益的方差或者股票的p值来衡量一只股票或股票组合的风险。通常股票投资组合的方差是由组合中各股票的方差和股票之间的协方差两部分组成，组合的期望收益率是各股票的期望收益率的加权平均。除去各股票完全正相关的情况，组合资产的标准差将小于各股票标准差的加权平均。当组合中的股票数目N增加时，单只股票的投资比例减少，方差项对组合资产风险的影响下降；当N趋向无穷大时，方差项将档近0，组合资产的风险仅由各股票之间的协方差所决定。也就是说，通过组合投资，能够减少直至消除各股票自身特征所产生的风险(非系统性风险)，而只承担影响所有股票收益率的因素所产生的风险(系统性风险)。
　　二、实现收益最大化
　　股票投资组合管理的目标之一就是在投资者可接受的风险水平内，通过多样化的股票投资使投资者获得最大收益。从市场经验来看，单只股票受行业政策和基本面的影响较大，相应的收益波动往往也很大。在公司业绩快速增长时期可能给投资者带来可观的收益，但是如果因投资者未观察到的信息而导致股票价格大幅下跌，则可能给投资者造成很大的损失。因此，在给定的风险水平下，通过多样化的股票选择，可以在一定程度上减轻股票价格的过度波动，从而在一个较长的时期内获得最大收益。

投资组合 portfolio investment

In economics and finance, Portfolio Investment represents passive holdings of securities such as foreign stocks, bonds, or other financial assets, none of which entails active management or control of the securities’ issuer by the investor; where such control exists, it is known as foreign direct investment.

Some examples of portfolio investment are:

purchase of shares in a foreign company.
purchase of bonds issued by a foreign government.
acquisition of assets in a foreign country.
Factors affecting international portfolio investment:

tax rates on interest or dividends (investors will normally prefer countries where the tax rates are relatively low)
interest rates (money tends to flow to countries with high interest rates)
exchange rates (foreign investors may be attracted if the local currency is expended to strengthen)
Portfolio investment is part of the capital account on the balance of payments statistics.

投资组合
投资组合 (Investment portfolio)，又名 资产投资组合，所重视的是资产，例如股票、债券、外币、期权、贵金属、衍生性金融商品、房地产、土地、古董、上市公司地位(俗称「壳」)、艺术品、及至红酒等。 一个投资组合是一个投资者手上持手的资产性投资组合的成分，其中可分类为进取型、保守型等。 一个优质的资产投资组合最理想的是具高流动性、平稳及较高收益、低投资风险等。

资产投资组合的成份不会包括消费品，例如跑车、电视机、化妆品、成衣等，因为它们都并无增值潜力，甚至只有折旧。

In finance, a portfolio is an appropriate mix of or collection of investments held by an institution or a private individual. In building up an investment portfolio a financial institution will typically conduct its own investment analysis, whilst a private individual may make use of the services of a financial advisor or a financial institution which offers portfolio management services. Holding a portfolio is part of an investment and risk-limiting strategy called diversification. By owning several assets, certain types of risk (in particular specific risk) can be reduced. The assets in the portfolio could include stocks, bonds, options, warrants, gold certificates, real estate, futures contracts, production facilities, or any other item that is expected to retain its value.

Management
Portfolio management involves deciding what assets to include in the portfolio, given the goals of the portfolio owner and changing economic conditions. Selection involves deciding what assets to purchase, how many to purchase, when to purchase them, and what assets to divest. These decisions always involve some sort of performance measurement, most typically expected return on the portfolio, and the risk associated with this return (i.e. the standard deviation of the return). Typically the expected return from portfolios of different asset bundles are compared.

The unique goals and circumstances of the investor must also be considered. Some investors are more risk averse than others.

Mutual fund have developed particular techniques to optimize their portfolio holdings. See fund management for details.

[edit] Porfolio formation
Many strategies have been developed to form a portfolio.

equally-weighted portfolio
capitalization-weighted portfolio
price-weighted portfolio
optimal portfolio (for which the Sharpe ratio is highest)

[edit] Models
Some of the financial models used in the process of Valuation, stock selection, and management of portfolios include:

Maximizing return, given an acceptable level of risk.
Modern portfolio theory—a model proposed by Harry Markowitz among others.
The single-index model of portfolio variance.
Capital asset pricing model.
Arbitrage pricing theory.
The Jensen Index.
The Treynor Index.
The Sharpe Diagonal (or Index) model.
Value at risk model.

Portfolio returns can be calculated either in absolute manner or in relative manner. Absolute return calculation is very straight forward, where return is calculated by considering total investment and total final value. Time duration and cash flow in portfolio doesn’t influence final return.

To calculate more accurate return of your investments you have to use complicated statistical models like Internal rate of return or Modified Internal Rate of Return. The only problem with these models are that, they are very complicated and very difficult to compute by pen and paper. You need to have a scientific calculator or some software. Both of these models consider all cash flow(Money In/Money Out) and provide more accurate returns than absolute return. Time is a major factor in these models.