Signatures of A Companion Star in Type Ia Supernovae

While type Ia Supernovae (SNe Ia) have been used as precise cosmological distance indicators, their progenitor systems remain unresolved. One of the key questions is if there is a non-degenerate companion star at the time of a thermonuclear explosion of a white dwarf (WD). In this paper, we investigate if an interaction between the SN ejecta and the companion star may result in observable footprints around the maximum brightness and thereafter, by performing multi-dimensional radiation transfer simulations based on hydrodynamic simulations of the interaction. We find that such systems result in variations in various observational characteristics due to different viewing directions, while the predicted behaviors (redder and fainter for the companion direction) are opposite to what were suggested by the previous study. The variations are generally modest and within observed scatters. However, the model predicts trends between some observables different from observationally derived, thus a large sample of SNe Ia with small calibration errors may be used to constrain the existence of such a companion star. The variations in different colors in optical band passes can be mimicked by external extinctions, thus such an effect could be a source of a scatter in the peak luminosity and derived distance. After the peak, hydrogen-rich materials expelled from the companion will manifest themselves in hydrogen lines. H$\alpha$ is however extremely difficult to identify. Alternatively, we find that P$_{\beta}$ in post-maximum near-infrared spectra can potentially provide powerful diagnostics.Comment: ApJ, accepted. 32 pages, 1 table, 23 figures, and 12 supplementary figure

Issue Cost and Method of IPO Underwriting: Japan's Change from Auction Method Pricing to Book Building

In 1997, Japan introduced book building an alternative to an auction method of IPO pricing that had been required since 1989. Shortly after its authorization, all IPOs in Japan were priced by book building. The shift occurred despite economic arguments and evidence suggesting that the auction method reduced underpricing. We attribute the shift to creation of an information-based pooling equilibrium where low quality firms that benefit from the imposed auction regime lose the benefit if high quality firms are free to select book building. We examine the effects of the regime change on total issue cost and characteristics of IPO firms. We find that, on average, total issue cost during the auction period would have been similar under book building, but that the regimes have differential effects. For large well-established issuers, book building reduced total issue cost. Small issuers had lower cost under the auction method, but high-quality small firms appear to have been foreclosed from issuing. Ignoring the effect of pricing method on underinvestment, our estimates of the simple average cost advantage of the auction method range from 6.9 percent of aftermarket value to –1.8 percent. Because, from a cost standpoint, book building benefits large issuers, the value-weighted effect of the book building method is unambiguously positive, averaging 136 million Yen per issuer in our sample, or 3.5 percent of aftermarket value. In aggregate, we estimate that reliance on the auction method from 1995 through late 1997 cost JASDAQ issuers 61 billion Yen more than book building would have cost. This estimate does not include any additional costs associated with underinvestment.

Issue Cost and Method of IPO Underwriting: Japan's Change from Auction Method Pricing to Book Building

In 1997, Japan introduced book building an alternative to an auction method of IPO pricing that had been required since 1989. Shortly after its authorization, all IPOs in Japan were priced by book building. The shift occurred despite economic arguments and evidence suggesting that the auction method reduced underpricing. We attribute the shift to creation of an information-based pooling equilibrium where low quality firms that benefit from the imposed auction regime lose the benefit if high quality firms are free to select book building. We examine the effects of the regime change on total issue cost and characteristics of IPO firms. We find that, on average, total issue cost during the auction period would have been similar under book building, but that the regimes have differential effects. For large well-established issuers, book building reduced total issue cost. Small issuers had lower cost under the auction method, but high-quality small firms appear to have been foreclosed from issuing. Ignoring the effect of pricing method on underinvestment, our estimates of the simple average cost advantage of the auction method range from 6.9 percent of aftermarket value to 1.8 percent. Because, from a cost standpoint, book building benefits large issuers, the value-weighted effect of the book building method is unambiguously positive, averaging 136 million Yen per issuer in our sample, or 3.5 percent of aftermarket value. In aggregate, we estimate that reliance on the auction method from 1995 through late 1997 cost JASDAQ issuers 61 billion Yen more than book building would have cost. This estimate does not include any additional costs associated with underinvestment

Why are IPOs underpriced? Evidence from Japan's hybrid auction-method offerings

Until October 1997, firms wishing to go public in Japan were required to use a hybrid auction process where up to half of the issue (the auction tranche) was offered to investors via a discriminatory auction. Remaining shares (the public offer tranche) were sold a few days later by a firm commitment at a fixed price. We document underpricing and partial adjustment of IPO public offer prices in Japan's auction regime, a regime where: investors are symmetrically informed or information differences are not important; roadshows are not held; preferential allocations to any investor are negligible; and institutional investing is low. The results raise important questions about theoretical interpretations of IPO underpricing in the U.S. We consider a broad range of competing, but non-mutually-exclusive, hypotheses about the reasons for underpricing and partial adjustment. Japan's auction-method evidence is most consistent with a quasicontractual allocation of risk related to initial mispricing. The risk allocation hypothesis is that, in exchange for guaranteeing a minimum price to the issuer, the underwriter participates indirectly in upside performance. The underwriter benefits from underpricing because underpriced IPOs are easier to place and because the underwriter can allocate small positions in the underpriced shares to preferred customers in implicit exchange for other benefits. As average underpricing in our sample is about three times as great as the underwriter's fee, and as some IPOs are severely underpriced, we cannot exclude the possibility that underpricing is affected by agency cost and prospect theory considerations similar to those suggested by Ritter and Welch (2002) in their review of the U.S. IPO market

Investor Activism in Japan: The First 10 Years

This paper provides a comprehensive examination of the first decade of investor activism in Japan. In the context of a remarkable transformation of the Japanese capital market, we document the rise of hedge fund and other investors with a total of 916 filings of block acquisitions by activists in the period from 1998 to 2009. We show that there is, on average, a (modest) positive stock price reaction to the announcement of an activist investment. These effects, however, are concentrated in events involving hostile funds. When we examine returns to activism in the long run we find that gains are not significant overall, except on positions in large target firms. We find that target firms tend to increase their payouts relative to peer firms in response to activist campaigns but we fail to find evidence that activists force target firm managers to institute major operational improvements. Finally we document the explosion in the adoption of "poison pills" by Japanese firms. We find that firms targeted by activists were more likely to adopt defense mechanisms. Since 2007 there has been a substantial reduction in activity by activist funds. Our paper contributes to the literature on investor activism by illustrating the limits to the success of activist funds in a market setting where the takeover market is thin and cannot be used by the activist investor as an "exit" strategy

複数の打ち返しからなる戦術の実現に向けたエアホッケーロボットの研究

本研究では，従来に開発された様々な打ち返し動作を含め，ロボットがゲーム状況や対戦相手の特徴に応じて複数回の打ち返し動作を攻撃パターンとして用いてゲームをおこなうことができるシステムの開発を目標としている．我々の研究室では，1回1回のロボットによる打ち返し動作をスキルと定義し，スキルを複数回組み合わせたラリーパターンを戦術と定義した上で，エアホッケーロボットによる戦術の実現を目指している．対戦相手やゲーム状況に応じて戦術を適宜変更しながら対戦することで，手筋が予想されにくくなることや，プレーヤーの特徴に基づいて対戦手法を変更することが可能となる．そこで本研究では，エアホッケーロボットによる戦術を実現するために，2層構造からなるアーキテクチャーを提案した．2層構造は，戦術を指令する上位モジュールである戦術レイヤーシステムと，指令された戦術を実行しようとゲームを自律的にプレーすることが可能な下位モジュールであるスキルレイヤーシステムの２つのシステムによって構成される．戦術レイヤーでは実行したい戦術をスキルレイヤーに送り，スキルレイヤーでは戦術の重みに加えて各スキルの発動可能性や，ロボットのキャラクターに基づいた重みの3つの要素を判断要素としスキルを選択することでスキルを適宜実行しゲームを継続してプレー可能となる．本研究では，スキルレイヤーをエアホッケーロボットシステムに搭載することで対戦相手とのゲームをおこなえるシステムを実現した．また，本研究では，戦術を構成するスキルのバリエーションを増やす目的として，ロボット側の陣でパックを保有するためのスキルを作成し，ロボットによる戦術の幅を広げることを目指した．このスキルを用いることにより，ロボットが打ち返されたパックを一旦手元で保有してから打ち返すなどといった緩急を加えた戦術の実現が可能となり，ゲーム状況に応じた戦術の選択肢の幅が拡張されることが期待される．最後に戦術実現に向けた2層構造システムを用いて複数のスキルから適宜スキルが切り変えをおこなえているかの実験をおこない，本システムが戦術実現に向けて有効的であることを示した．電気通信大学201

Investor Activism in Japan: The First 10 Years

This paper provides a comprehensive examination of the first decade of investor activism in Japan. In the context of a remarkable transformation of the Japanese capital market, we document the rise of hedge fund and other investors with a total of 916 filings of block acquisitions by activists in the period from 1998 to 2009. We show that there is, on average, a (modest) positive stock price reaction to the announcement of an activist investment. These effects, however, are concentrated in events involving hostile funds. When we examine returns to activism in the long run we find that gains are not significant overall, except on positions in large target firms. We find that target firms tend to increase their payouts relative to peer firms in response to activist campaigns but we fail to find evidence that activists force target firm managers to institute major operational improvements. Finally we document the explosion in the adoption of "poison pills" by Japanese firms. We find that firms targeted by activists were more likely to adopt defense mechanisms. Since 2007 there has been a substantial reduction in activity by activist funds. Our paper contributes to the literature on investor activism by illustrating the limits to the success of activist funds in a market setting where the takeover market is thin and cannot be used by the activist investor as an "exit" strategy

Banking relationships and access to equity capital markets: evidence from Japan's main bank system

We study the role of banking relationships in IPO underwriting. Among other issues, we consider whether banking relationships lead to increased access to public equity markets, especially for smaller, lesserknown firms. When a firm in Japan goes public, it can engage an investment bank that is related through a common main bank, or can select an alternative investment bank. The main bank relationship can be an efficient way for the investment bank to acquire information generated by the main bank, but may give rise to conflicts of interest. We use data from two different investment banking regimes in Japan (a hybrid auction-method regime and a book-building regime) and find that main bank relationships give small issuers increased access to equity capital markets, but that issuers of large IPOs switch to non-related investment banks that are capable of managing large offerings. While we find evidence that investment banks seek to exploit bargaining power with related issuers, we also find that issuers respond to expected high issue cost by switching to non-related investment banks. The net result is that total issue costs through related and non-related investment banks are similar. With respect to aftermarket performance and use of offer proceeds, we find no evidence of conflict of interest or self-dealing for either the main bank or the investment bank