One of the most crucial criterion in automated negotiation is how to reach a consensus agreement for all negotiators under any negotiation environment. Currently, most negotiation strategies can work under the static environment only. This paper presents a model for designing negotiation agents that makes adjustable rates of concession by reacting to changing market situations with uncertain and dynamic outside options. This work is based on the model of market-driven agents (MDAs). To determine the amount of the concession for each trading cycle, these market-driven agents are guided by four mathematical functions of trading opportunity, trading competition, trading time and strategy and trading eagerness. The contribution of this paper is designing and developing an extended MDA model with the flexibility to respond to uncertain and dynamic outside options, so as to increase problem solving ability for agent negotiation in broad application domains.