(27)Reverse repurchase agreements should be able to be used by MMFs as a means to invest excess cash on a very short-term basis, provided that the position is fully collateralised. In order to protect investors, it is necessary to ensure that the collateral provided in the framework of reverse repurchase agreements is of high quality and does not display a high correlation with the performance of the counterparty, in order to avoid a negative impact in the event of default of the counterparty. In addition, an MMF should be allowed to invest in repurchase agreements up to a limit of 10 % of its assets. Other efficient portfolio management techniques, including securities lending and borrowing, should not be used by an MMF as they are likely to impinge on achieving the investment objectives of the MMF.