本文探討公司金字塔結構的投資層級多寡與公司避稅活動的關聯性。本文預期，當投資層級愈多，公司與金融市場之間的資訊不對稱及代理問題愈大，公司愈容易透過投資層級進行避稅，降低公司的有效稅率。因台灣公開交易公司依法需揭露其所有的關係企業，故本文以台灣公開交易的非金融公司為樣本，實證發現，投資層級的數量與公司避稅活動（有效稅率）呈現正向（反向）關係。此外，當公司較多的關係企業設立在避稅天堂時，此正向關係更為明顯。整體而言，實證結果支持以下論述－當公司投資層級愈多，母公司愈容易透過關係企業之間的交易來進行避稅活動並避免檢查。

This study investigates whether the span of corporate pyramids (as measured by the number of ownership layers) is associated with a firm’s tax avoidance activities. Using a unique sample of publicly traded non-financial firms of Taiwan, which are required to disclose information on all of their affiliates, we measure the span of corporate pyramids using the number of layers in them. Consistent with corporate pyramids generating higher agency costs and information asymmetries, we find that firms with a large number of layers engage in more tax avoidance activities, leading to lower effective tax rates. Furthermore, we find that the well-documented positive association between the level of tax avoidance and having investees in tax havens becomes more pronounced as the number of layers increases. Overall, the results support the argument that the length of pyramidal layers allows the parent firm to conduct intercompany transactions to prevent inappropriate tax avoidance activities from detection.