A causal link exists between the ability of investors to trade risk and market liquidity. More liquid markets are likely to attract investors whose strategies involve frequent trading, and such investors will in turn contribute to increased market liquidity. The contribution of hedge funds to market liquidity is frequently noted (e.g., Crockett 2007). In addition, less financialized investors can have an interest in restricting the increased financialization of the market structure, and in certain cases will have the ability to do so (see Chapter 2). Overall, a focus solely on market liquidity obscures as much as it reveals. It provides objective measurement, for example, through turnover figures and the difference (spread) between buying and selling (bid-offer) prices (see below and Committee on the Global Financial System 2007). The question of market resilience, a key component of liquidity that is especially important at times of market stress, remains difficult to measure objectively (Committee on the Global Financial System 2007: 46). It does not consider, also, the types of investors active in a market, and the implications of this. Liquidity, therefore, is a third example of a variable that covers only a part of the necessary range of analysis.