全球併購與累積平均異常報酬之影響因素：香港上市公司的實證研究

Abstract

當前競爭激烈的商業環境下, 以併購方式來達成企業的外部成長, 己成為常見的策略手段之一。併購活動除了在已開發國家中盛行,在新興經濟體, 例如台灣、香港等地方亦日漸揚升, 本研究針對同為新興經濟體、同為亞洲四小龍的香港主併者, 進行全球併購時國內股市所產生之累積平均異常報酬的分析, 以及其影響因素的研究, 以對照過去以西方及台灣企業為樣本的研究結果。 本研究的購併案資料來源為SDC 資料庫, 樣本取樣期間為1/1/1990 至12/31/2007, 取樣標的為香港主板及創業板公司為併購案中之主併者, 且該併購案之交易金額最少需為1000萬美元, 總計有551 個研究樣本。此外, 各樣本相關的股市資訊乃是由Datastream 資料庫中取得, 並以MatLab 程式軟體計算出累積平均異常報酬以檢測。本研究採用以下兩種研究方法: 針對累積平均異常報酬現象的分析, 乃運用事件研究法; 而對於累積平均異常報酬的影響因素則採t 檢定和ANOVA 檢定。 本研究顯示, 此551 個合併案的主併者, 其累積平均異常報酬顯著大於0, 印證了多數過去七方的研究結論。而在潛在影響因素的部份, 本研究提出六個可能因子並深入探討, 包括: 多角化程度、宣告年度、區域配對、相對規模、交付方式, 及目標公司公開發行狀況。在「相對規模」及「交付方式」方面, 本研究發現, 當目標公司相對規模愈大、或以股票或部份股票及部份現金交易時, 該併購案的正向異常報酬顯著優於相對規模較小、以現金交付的併購案; 而在「多角化程度」、「宣告年度」、及「目標公司公開發行狀況」方面, 本研究發現, 當多角化程度低、宣告年度於1998 年後、及目標公司為非公開的情況下(private/subsidiary), 主併者有有顯著正向異常報酬, 且這些因素對於累積平均異常報酬有部份解釋能力。至於「區域配對」, 本研究發現香港主併者和東方華人地區的公司併購時, 有顯著平均異常報酬, 顯示併購後的整合問題亦為投資人考量的一個原因。上述研究發現大致和歐美研究結果吻合, 而與台灣研究多所出入, 此原因可能是臺灣股市結構與美股不同, 而香港股市結構與美股頗為類似所致。

In the hypercompetitive global marketplace, business growth by mergers and acquisitions (M&A) has been a widely adapted strategy. M&A thrives not only in developed Western countries but also in emerging markets such as Taiwan and Hong Kong over the past ten years. Acquirers of Hong Kong, as a member of “East Asian Four Tigers” similar to Taiwan, were used to examine the cumulative average abnormal returns (CAR) of M&A as well as the potential determinants of CAR. The M&A data were collected from SDC database with the sampling period from 1/1/1990 to 12/31/2007. The researc samples are the companies publicly listed in Hong Kong Main Board and Growth Enterprise Market (GEM) which act as the acquirers in the M&A cases with the transaction scale higher than USD 10 million. In total, 551 qualified cases were included in this research. The stock market related information was collected from Datastream database and the CAR was further calculated by the MatLab software program. Two analytical methods are employed in this research. For the investigation on the CAR, the event study serves; for the analysis of the determinants of CAR, the t-test and ANOVA functions. The research findings confirm the existence of CAR. As to potential determinants, six factors were used and examined: diversification, period announced, region match, relative size of the target, method of payment, and target public status. The findings show that large relative size and M&A cases paid with stock or mix of stock and cash have significantly positive CAR and outperform counterparties. In addition, lower degree of diversification, year announced after 1998, and private or subsidiary targets tend to have significantly positive CARs. As to region match, it shows that local M&A has significantly positive CARs, implying that the post-merger integration issues matter. In sum, our research findings are largely consistent with those of prior Western research, probably because that the stock market of Hong Kong is well developed and similar to the market structure of New York Stock Exchange (NYSE).