比特幣曾被視為如同黃金一樣的避險性資產，但比特幣價格在2020-2022疫情期間大幅震盪的表現，卻又像是銅一樣的風險性資產。本研究以比特幣價格、銅價、黃金價格為分析對象，以S&P500指數作為投資人景氣觀測指標，美國領先經濟指標(LEI)作為消費者及製造業景氣預測指標，選取2016年1月至2022年10月之月資料，藉由Granger因果關係檢定分析各變數的時間序列資料，探討比特幣價格、銅價、黃金價格是否會受到景氣波動的影響。並利用預測誤差變異數分解及衝擊反應函數來分析變數間的動態特性，以區分比特幣、銅以及黃金的商品屬性。
研究結論歸納如下:
一、因果關係檢定顯示，美國領先經濟指標(LEI)單向領先銅價；S&P500指數單向領先比特幣價格。因此美國領先經濟指標可用來預測銅價未來的趨勢，S&P500指數則可用來預測比特幣價格未來的趨勢。
二、美國領先經濟指標對比特幣價格及銅價的衝擊反應為正向;S&P500指數對比特幣的衝擊反應短期為負向，長期轉為正向;黃金則只受自身前期值的影響。故推論比特幣兼具投機及原物料商品的特性，銅較偏向於原物料商品，黃金則較不受景氣波動影響，屬於避險性商品。

This study aims to investigate the co-movement and Granger causality between Bitcoin prices, copper price ,gold price,S&P 500 index and LEI.Assume the S&P 500 index as the economic forecasts by investors, and the US leading economic index (LEI) as the economic forecasts by manufacturing, It uses monthly data from from January 2016 to October 2022. By analyzing the time series data of each variables through Granger causality test, we can explore whether the price of bitcoin, copper and gold will be affected by economic fluctuations. Variance decomposition of forecast errors and impulse response function are used to analyze the dynamic effect between variables to distinguish the attributes of bitcoin, copper and gold.The empirical results show that:
1. US Leading Economic Index (LEI) Granger cause copper prices; S&P 500 index Granger cause Bitcoin price. These findings may help investors make investment decisions .
2. LEI effects on Bitcoin and Copper are positive , while the short-term effects of S&P 500 index on Bitcoin prices are negative.Gold is only affected by its own previous value. Therefore, it is inferred that Bitcoin has the characteristics of both speculation goods and commodities, copper is more inclined to commodities, and gold is less affected by economic fluctuations, which is a safe-haven asset.

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