只能找到摘要，帮不上了。
Time-varying hedge ratios have been found successful in reducing spot market risk in different commodity and financial futures markets. This article extends the empirical evidence by investigating the same question for a futures market based on services, the Baltic International Freight Futures Exchange (BIFFEX) market. BIFFEX contracts are cash settled against the Baltic Freight Index (BFI), a weighted-average dry cargo freight rate index, compiled from actual freight rates on 11 shipping routes that are dissimilar in terms of vessel sizes and transported commodities. GARCH and augmented GARCH models are introduced to investigate the hedging effectiveness of the futures contract across the different shipping routes. Time-varying hedge ratios outperform alternative specifications in reducing market risk in four shipping routes, but they fail to reduce the riskiness of the spot position to the extent found for other markets in the literature. This is explained by the fact that freight futures contracts are employed as a cross-hedge against the fluctuations of the individual shipping routes that constitute the underlying index. There is large basis risk, and the rate fluctuations on these routes may not be accurately tracked by the futures prices. A recent change in the contract's underlying index appears to have substantially increased hedging effectiveness, but not trading activity as yet. [ABSTRACT FROM AUTHOR]

多谢啊 大家再帮帮忙 想想办法啊