invest the account funds. According to one report, in practice no examples of 100 percent reserve banking are known to exist.) Non-banking finance Islamic non-banking finance has grown to encompass a wide range of services, but as of 2013, banking still dominates and represented about four-fifths of total assets in Islamic finance. The sukuk market is also a fast-growing segment with assets equivalent to about 15 percent of the industry. Other services include leasing, equity markets, investment funds, insurance (takaful), and microfinance. These products—and Islamic finance in general—are based on Islamic commercial contracts (aqad i.e. a commitment between two parties) and contract law, with products generally named after contracts (e.g. mudaraba) though they may be combinations of more than one type of contract. Profit and loss sharing While the original Islamic banking proponents hoped profit-loss sharing (PLS) would be the primary mode of finance replacing interest-based loans, long-term financing with profit-and-loss-sharing mechanisms is "far riskier and costlier" than the long term or medium-term lending of the conventional banks, according to critics such as economist Tarik M. Yousef. Yousef and other observers note that musharakah and mudarabah financing have "declined to almost negligible proportions".Kuran, Timur. 2004. Islam and Mammon: The economic predicaments of Islamism. Princeton, NJ; Princeton University PressYousef, T. M. 2004. The murabaha syndrome in Islamic finance: Laws, institutions and policies. In Politics of Islamic finance, ed. C. M. Henry and Rodney Wilson. Edinburgh: Edinburgh University Press In many Islamic banks asset portfolios, short term financing, notably murabaha and other debt-based contracts account for the great bulk of their investments. Mudarabah A "mudarabah" (profit sharing) contract is a kind of partnership where one partner (rabb-ul-mal) gives money to another (mudarib) for investing in a commercial enterprise. The "sleeping" rabb-ul-mal party provides 100 percent of the capital. The mudarib party provides its expertise and management. Profits generated are shared between the parties according to a pre-agreed ratio—usually either 50%-50%, or 60% for the mudariband 40% for rabb-ul-mal. If there is a loss, the first partner "rabb-ul-mal" will lose his capital, and the other party "mudarib" will lose the time and effort invested in the project. The structure of mudaraba is very similar to that of venture capital where the venture capitalist finances the entrepreneur who provides management and labor, so that both profit and risk are shared. Such participatory arrangements between capital on one hand and labor and management on the