Traditionally, those sophisticated investors that hold large portfolios of assets such as medium to long term bonds generating low annuities may often be inclined to enter enhancement opportunities that allows them to receive additional returns over their portfolios. Generally these investors would enter into collateral transfer agreements allowing their assets to be used by third parties who pay them a rental fee and who enter into contract with them. This allows the investor to retain ownership of his assets and continue to receive his annuities thereon. In addition, the investor will receive additional returns from the rental fee giving him an enhanced return over his assets. By collecting these assets into a pool and placing them with a world-renowned and acceptable bank, the investor will instruct the issue of a Bank Guarantee using these assets as the security. This Bank Guarantee will be sent to the receiving party. The receiving party will often credit line the Bank Guarantee in the usual way, see Credit Lining Bank Guarantees. Investors may be motivated to enter into collateral transfer agreements due to under-performance of their existing portfolios or where their portfolio has no annuity or is long-term. Some may be motivated by the quick returns that can be achieved. Investors acting is this way may be referred to as “Providers” of collaterals. It is a growing area of collateral management.