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Speculative Bubbles In The Recent Ai Boom: Nasdaq And The Magnificent Seven, Rerotlhe B. Basele, Peter C. B. Phillips, Shuping Shi Sep 2025

Speculative Bubbles In The Recent Ai Boom: Nasdaq And The Magnificent Seven, Rerotlhe B. Basele, Peter C. B. Phillips, Shuping Shi

Research Collection School Of Economics

The recent artificial intelligence (AI) boom covers a period of rapid innovation and wide adoption of AI intelligence technologies across diverse industries. These developments have fueled an unprecedented frenzy in the Nasdaq, with AI-focused companies experiencing soaring stock prices that raise concerns about speculative bubbles and real-economy consequences. Against this background, this study investigates the formation of speculative bubbles in the Nasdaq stock market with a specific focus on the so-called Magnificent Seven (Mag-7) individual stocks during the AI boom, spanning the period from January 2017 to January 2025. We apply the real-time PSY bubble detection methodology of Phillips et …


Price Comovement And Market Segmentation Of Chinese A- And H-Shares: Evidence From A Panel Latent-Factor Model, Yingjie Dong, Wenxin Huang, Yiu Kuen Tse Mar 2023

Price Comovement And Market Segmentation Of Chinese A- And H-Shares: Evidence From A Panel Latent-Factor Model, Yingjie Dong, Wenxin Huang, Yiu Kuen Tse

Research Collection School Of Economics

This paper examines the price comovement of cross-listed Chinese A- and H-shares using a panel model with latent factors and a heterogeneous long-run structure. Our model is more flexible than the cointegration system and is estimated using the data-driven Cup–Lasso method. The long-run H-share price discounts are heterogeneous across different groups of stocks. We have identified both stationary and nonstationary latent factors in the price differentials, which are driven by different economic variables. By analyzing the factor loadings of the nonstationary latent factor, we identify some trading-friction and information-friction variables that have effects on the price convergence between the A- …


Forecasting Equity Index Volatility By Measuring The Linkage Among Component Stocks, Yue Qiu, Tian Xie, Jun Yu, Qiankun Zhou Jan 2022

Forecasting Equity Index Volatility By Measuring The Linkage Among Component Stocks, Yue Qiu, Tian Xie, Jun Yu, Qiankun Zhou

Research Collection School Of Economics

The linkage among the realized volatilities of component stocks is important when modeling and forecasting the relevant index volatility. In this article, the linkage is measured via an extended Common Correlated Effects (CCEs) approach under a panel heterogeneous autoregression model where unobserved common factors in errors are assumed. Consistency of the CCE estimator is obtained. The common factors are extracted using the principal component analysis. Empirical studies show that realized volatility models exploiting the linkage effects lead to significantly better out-of-sample forecast performance, for example, an up to 32% increase in the pseudo R2. We also conduct various forecasting exercises …


Intraday Value-At-Risk: An Asymmetric Autoregressive Conditional Duration Approach, Shouwei Liu, Yiu Kuen Tse Dec 2015

Intraday Value-At-Risk: An Asymmetric Autoregressive Conditional Duration Approach, Shouwei Liu, Yiu Kuen Tse

Research Collection School Of Economics

We propose to compute the Intraday Value-at-Risk (IVaR) for stocks using real-time transaction data. Tick-by-tick data filtered by price duration are modeled using a two-state asymmetric autoregressive conditional duration (AACD) model, and the IVaR is calculated using Monte Carlo simulation based on the estimated AACD model. Backtesting results for the New York Stock Exchange (NYSE) show that the IVaR calculated using the AACD method outperforms those using the Dionne et al. (2009) and Giot (2005) methods.


The Labor Supply And Welfare Effects Of Early Access To Medicare Through Social Security Disability Insurance, Kim Nov 2012

The Labor Supply And Welfare Effects Of Early Access To Medicare Through Social Security Disability Insurance, Kim

Research Collection School Of Economics

Social Security Disability Insurance (SSDI) beneficiaries receive a cash benefit and become eligible for health insurance from Medicare two years after their enrollment. Disabled workers who leave the labor force typically lose health insurance from their employers, and they face significant medical expenditure risk as a result of their disability. Therefore, access to Medicare makes SSDI an especially attractive alternative to remaining employed for workers with disabilities. My research is the first to analyze the importance of medical expenditure risk and Medicare in analysis of SSDI, and it addresses the following questions: (1) How does access to Medicare via SSDI …