The phrase is about investments, not loans, so in this case it is not about availability of funds or funds.

In the case of investments, maximum drawdown agreements are agreements whereby brokerage firms agree to cap a trader's loss if the market goes south.

Specifically, traders or 'investors' can take on positions in the equities, futures, forex or other markets with brokerage firms on margin. That is, the traders can leverage themselves by not paying the full amount and just place a margin balance in their account to cover eventual losses that the broker may have to incur in if he has to close out the position due to market fluctuations before the trader/investor liquidates by paying the full amount or reversing the transaction. This is typical in the futures market, but is also possible on the spot markets.

Under a maximum drawdown agreement, a broker basically assumes the responsibility for closing out the transaction it goes against the trader before a given loss (the drawdown) is sustained by the trader. Thus, the broker in essence caps the trader's loss. He can do so since he has the margin account to cover any variations, but is taking on the full risk in case of a spike, market collapse, etc.

Ahora, como decirlo en español? La pérdida queda limitada al margen o una porción del margen, y el corredor se responsabiliza de liquidar la operación o cerrar la posición a fin de acotar dicha pérdida. Quizás alguien tenga un término mejor, pero se me ocurre: Garantía de Pérdida Máxima, que es lo que en realidad es. Sugiero mantener el término en ingés entre comillas para beneficio de los entendidos.