過去文獻認為公司IPO後長短期績效存在著顯著的差異，且因所屬的產業別不同也有所差異。本研究以台灣LED產業在2001年至2007年之間IPO公司為樣本，篩選出533筆有效樣本，其中包括上、中下游及相關應用企業共26家。本研究發現在台灣LED產業中，公司在產業價值鏈地位及IPO時間與股價淨值比呈顯著相關。上游企業隨IPO時間的增長，股價淨值比明顯遞增；而中下游企業卻隨IPO時間的增長，股價淨值比緩慢遞減，這與台灣LED產業群聚網路發展及整合發揮綜效有關，同時由於上、中下游企業處於不同產品生命週期的階段，市場對於其未來的成長性給予不同評價。

Previous studies have shown there are substantial differences between short-run and long-run performances of firms in post-IPO. The firm value also undergoes obvious changes depending on their industries. This paper examines the relationship between IPO age and P/B ratio for the Taiwanese LED industry. The effective sample consists of 26 firms with 533 sample observations with regards to their IPO between 2001 and 2007. The empirical results finds (1) In the Taiwanese LED industry, a firm's position in the industry value chain, and the IPO age jointly affect the P/B ratio. (2) The long-run performance is not always worse than the short-run performance after the LED firm's IPO. The performance depends on the firm's position in the industry value chain. For upstream firms, P/B ratio will increase significantly along with the increasing IPO age. For mid and downstream firms, P/B ratio decreases slowly as time passes with the IPO. These characteristics could be related to the integration and synergy of industry clusters, or as the result of different evaluations by investors towards different products along the value chain at different stages of the product life cycle. The results indicate that the accumulation of experience and skills directly influence the firm's value depending on their role in the value chain, and indirectly influence the development of the entire LED value chain.