초록 close

내부자거래란 공개되지 않은 중대한 기업 정보를 바탕으로 증권을 거래하는 행위이다. 미국에서 기업의 내부자들의 증권거래는 1934년 제정된 증권거래법(Securities and Exchange Act of 1934) 이래로 명시적으로 규제되어 왔고, 판례로는 1968년에 처음 등장하였다. 크게 주목받지 못하던 내부자거래가 본격적으로 대중의 주목을 받게 된 것은 1980년대 활발한 인수합병 때문이었고, 이 때문에 증권감독당국인 SEC(Securities and Exchange Commission)에서는 대대적인 감시 및 감독 강화와 함께 연방법 개정을 추진하여 1984년 내부자거래 금지법(Insider Trading Sanctions Act of 1984)과 1988년 내부자거래와 증권사기 규제법(Insider Trading and Securities Fraud Enforcement Act of 1988)이 탄생하였다. 본고에서는 1980년대 미국의 내부자거래 규제 강화를 배경으로 기업내부자들의 거래 행태 변화를 추적하고 이러한 거래 행태가 인수합병과 관련하여 차이가 있었는지 및 시장의 거래에 영향이 있었는지를 분석하였다. 그 결과, 1980년대의 두 차례에 걸친 대대적인 내부자거래 규제의 강화로 인해 기업 내부자들의 거래가 위축된 것 같지 않으며, 인수․합병된 회사들의 내부자들이 그렇지 않은 회사들의 내부자들에 비해 더 활발히 주식을 거래하고 있었다고 보기도 어렵다. 오히려 총주식수에 대비했을 때 인수합병되지 않은 회사들의 내부자거래량이 더 많았다고 보는 것이 타당하다. 또한, 기업내부자의 거래에 대한 시장의 반응은 1989년이 1983년에 비해 크게 나타났고 인수합병된 회사들에 대해서는 기업내부자들의 매도 행위에 대한 시장 반응이 두드러졌던 반면, 인수합병되지 않은 회사들에 대해서는 내부자들의 매수 행위가 더 큰 반응을 일으켰던 것으로 나타났다.


Corporate insiders have long been regulated explicitly since the Securities and Exchange Act of 1934 in the US. In the 1980s, insider trading received increased attention mainly because of active M&A activities, and the SEC(Securities and Exchange Commission) leveled up their interest in insider trading, which resulted in more insider trading cases and reinforced statutory sanctions, such as Insider Trading Sanctions Act of 1984 and Insider Trading and Securities Fraud Act in 1988. While the corporate world was neither able nor inclined to defend itself against regulation supporters, insider trading has remained controversial in scholarly journals. The most common argument against insider trading is that insider trading erodes public confidence in capital markets, raises firms’ cost of capital, and makes it more difficult finance worthwhile projects. Alternative view in favor of allowing insider trading is that corporate insiders’ trading is a contractual arrangement to compensate insiders for their innovations without costly renegotiations. This paper studies corporate insiders’ trading behaviors related with mergers and acquisitions in the 1980s, when insider trading sanctions were substantially reinforced. Specifically, the followings are discussed: First, does trading by corporate insiders in merged firms reduce after sanction reinforcement? Second, do insiders in eventually merged or acquired firms buy or sell more shares than those in non-M&Aed firms before M&A announcement? Finally, does insiders’ buying or selling activity have an effect on overall trading in the market? To answer the questions, I compare the amount of insider trading of M&Aed firms and non-M&Aed firms in 1983 and 1989, between which statutory sanctions are significantly reinforced and a major insider trading scandal(Boesky scandal) occurred, and estimate the effects of insiders’ buying or selling on general trading in stock exchanges. Specifically, I obtain the coefficient estimates of insiders’ buying or selling amounts in estimation equations where ‘abnormal trading volume’-trading volume which is not explained by the ‘market model for volume’- is used as the dependent variable. The sample group of M&Aed firms consists of 114 corporations, 44 of which were acquired or agreed to be acquired in 1983 and 70 in 1989. The control group is composed of respective 91 and 86 corporations, randomly chosen from the same industries of the sample firms but note acquired by the end of 1985 and 1991. The reason for the control group in the same industries is to properly filter out the ‘news media effect’ on trading volume, that is, to control abrupt changes in trading volume caused by M&A-related new and rumors. All the sample and control firms are chosen from 9 industries, which are energy, food, metal producing, machinery, electrical and electronics, measurement equipment, business services, computer and data processing, and health services. I choose these 9 industries because M&A prevailed in those industries in 1983 and 1989, and it is also advantageous to limit the number of industries for controlling industrial heterogeneity. The daily stock trading volume of the firms are retrieved from the Center for Research in Security Prices (CRSP) and trading records of the firms’ insiders are manually collected from the SEC’s ‘Official Summary.’ In spite of insider trading sanction reinforcement, corporate insiders’ trading did not curtail significantly, nor was more the M&Aed firms’ insider trading than that of non-M&Aed firms. Compared to the total shares outstanding, insider trading of non-M&Aed firms was more active than that of M&Aed firms, and insider trading for non-merged firms in 1983 was much more active than that in 1989. Another feature to note is that corporate insiders sell much more than they buy in the market, and that this is more severe for merged firms. Regarding the market’s response to corporate insider trading, two things are noticeable. First, market was more responsive to corporate insiders’ trading in 1989 than in 1983. For example, in 1983, a hundred shares bought by insiders a day caused 54 shares to be traded on the same day in the market without any particular reason, while the abnormal trading volume caused by insiders’ purchasing hundred shares rises six times to 325 shares, that is, insider’s buying a share is resonated more in the market in 1989. Second, for merged firms, insiders’ selling activity raised abnormal trading, while for non-merged firms, insiders’ purchasing evoked reactions in th market. When corporate insiders in merged firms purchase shares, abnormal trading volume of the firms did not particularly increases, whereas 100 shares purchased by corporate insiders in non-merged firms raise abnormal trading volume by 62 shares. The situation is reversed for selling activity: The market readily responded to selling out by insiders in merged firms by increasing trading volume by 71 shares corresponding to 100 sold shares, while it increased only 4 shares with respect to 100 sold shares by corporate insiders in non-merged firms, whire the figure is not even significant. From these results, I argue that speculative trading came to rely more on trading by corporate insiders in 1989, because increased insider trading sanctions reduced M&A-related information leaks, and speculative trading was sophisticated enough to distinguish M&A-based corporate insiders’ trading.