增量。属于投资。

这个疑问来自J. Wurgler. 2000. "Financial markets and the allocation of capital." Journal of Financial Economics, 58(1-2), pp. 187-214.，起初我也理解成增量。宏观数据里，比如年鉴，以前是叫“全社会资本形成总额”（大概就是从gross capital formation来的），后来叫“全社会固定资产投资”，都是增量，“以货币形式表现的在一定时期内全社会建造和购置固定资产的工作量以及与此有关的费用的总称”。但是看了国内的一篇follow J. Wurgler. 2000 的研究：方軍雄. 2006. "市場化進程與資本配置效率的改善." 經濟研究, (05), pp. 51-62、方軍雄. 2007. "所有制、市場化進程與資本配置效率." 管理世界, (11), pp. 27-35.，里面只笼统的说“固定资产的原值”，就觉得很奇怪，不清楚他用的是增量还是存量。

正好用到，太感谢了！！！！！

维基百科对capital formation的3种解释，我觉得可以取第一种，增量概念。
（1）It is a specific statistical concept used in national accounts statistics, econometrics and macroeconomics. In that sense, it refers to a measure of the net additions to the (physical) capital stock of a country (or an economic sector) in an accounting interval, or, a measure of the amount by which the total physical capital stock increased during an accounting period. To arrive at this measure, standard valuation principles are used.[1]
（2）It is used also in economic theory, as a modern general term for capital accumulation, referring to the total "stock of capital" that has been formed, or to the growth of this total capital stock.[2]
（3）In a much broader or vaguer sense, the term "capital formation" has in more recent times been used in financial economics to refer to savings drives, setting up financial institutions, fiscal measures, public borrowing, development of capital markets, privatization of financial institutions, development of secondary markets. In this usage, it refers to any method for increasing the amount of capital owned or under one's control, or any method in utilising or mobilizing capital resources for investment purposes. Thus, capital could be "formed" in the sense of "being brought together for investment purposes" in many different ways. This broadened meaning is not related to the statistical measurement concept nor to the classical understanding of the concept in economic theory. Instead, it originated in credit-based economic growth during the 1990s and 2000s, which was accompanied by the rapid growth of the financial sector, and consequently the increased use of finance terminology in economic discussions.

遇到了同样的问题，贴一个世界银行对Gross Capital Formation的定义供后续搜到的朋友参考。
-资本形成总额（以前称为Gross Domestic Investment 国内投资总额）包括经济体固定资产增加的支出加上库存水平的净变化。 固定资产包括土地改良（栅栏、沟渠、排水沟等）； 厂房、机械和设备采购； 以及道路、铁路等建设，包括学校、办公室、医院、私人住宅以及商业和工业建筑。 库存是公司为应对生产或销售的临时或意外波动而持有的货物库存，以及“在制品”。 根据 1993 年国民账户体系，贵重物品的净收购也被视为资本形成。