Abstract: Due to limited capital, single business and operational risk, the great majority of small-and-medium-sized retailing firms are often faced with shortage of funds. What's more, it is difficult to solve shortage of operational capital through external financing owning to be incapable of providing sufficient collateral. In the absence of financing opportunities, operating decisions of the retailers will inevitably be subject to their own operating funds, and this in turn results to exert an important impact on supply chain coordination. To discuss impact of shortage of operational capital on coordination of the supply chain, in this paper a model is constructed on contract coordination of a supply chain composed of one supplier and one retailer, where the retailer's funds are used in two ways:one is the procurement of goods and the other is promotional activities. In particular, more attention is paid to impact on coordination contracts of the retailer's operating capital and funds rate.
Firstly, on the assumption that there doesn't exist financing opportunities for the retailer, it investigates supply chain coordination via revenue sharing contract and buyback contract, respectively. A contract is called as type I coordination contract if it not only can coordinate the supply chain, but also can achieve arbitrary revenue allocation of the entire supply chain, and a contract is called as type II coordination contract if it can coordinate the supply chain, but can't achieve arbitrary allocation of the supply chain revenue. According to the retailer's operating funds, revenue sharing contract is divided into either type I coordination contract or type II coordination contract, and buyback contract has three different categories:type I coordination contract, type II coordination contract and non-coordination contract.
Secondly, it characterizes a critical condition for revenue sharing contract and buyback contract, respectively, which can be used to determine what type of contract belongs to. This condition can be expressed by the retailer's operating funds and the bargaining powers of the channel members. Equivalence of the two contracts is as well discussed, which leads to conclusion as follows. The two contracts are not always equivalent if the retailer is confronted with capital constraint. Put particular words, if the retailer's funds are very abundant, the two contracts are totally equivalent; if the retailer's funds are relatively abundant, the two contracts are partly equivalent; if the retailer's lack of funds, the two contracts are no longer equivalent. The difference that the two contracts coordinate the supply chain with financial constraints lies in:the revenue sharing mechanism possess financing function in nature (the supplier provides financing for the retailer), but the buyback contract does not have this function.
Last but not least, it explores impact of financial time value on supply chain coordination in the two contracts, and the results show that it is more likely to make use of buyback contract to succeed in coordination of the supply chain as the funds rate rises. However, the funds rate has no effect on revenue sharing contract. In the case of buyback contract, as the funds rate increases, the wholesale price decreases and the buyback price holds unchanged. In the case of revenue sharing contract, the time value of funds does not exert an effect on the likelihood that the supply chain can be coordinated.
From discussion some managerial insight is obtained, which can provide theoretical reference on contract coordination for the supply chains confronted with capital constraint.

Key words: supply chain coordination, capital constraint, revenue sharing contract, buy-back contract