Finance Brown Bag Seminar

Scholars at WU, the PhD students of VGSF as well as international guests present their working papers for discussion in the Brown Bag Seminar. The seminar is organized by our Institute together with the Institute for Financial Research, the Vienna Institute of Finance and the Vienna Graduate School of Finance.

It usually takes place on Wednesdays from 12:00 to 13:00 (location tba). For further information, please contact bbs-finance@wu.ac.at

• December 16, 2026 / 12:00–13:00 / TC.3.06
  Thu Nguyen (Vienna University of Economics and Business) 
  
   

• November 18, 2026 / 12:0013:00 / room tba
  Giorgio Ottonello (Vienna University of Economics and Business)
  Shadow Discounts (with Tomy Lee, Isacco Lotti, Florian Nagler and Chaojun Wang)
  
  Abstract: Centralized trading platforms should improve competition in OTC markets. Using transaction records from the U.S. corporate bond market and exploiting variation within client-dealer relationships, we find no evidence that clients receive better secondary-market trading terms after adopting a platform. To reconcile this puzzling finding, we present a model in which relationship dealers operate in both primary and secondary markets. A central insight, for which we find strong empirical support, is that dealers respond to clients‘ improved outside options not by changing secondary-market terms, but by granting larger primary-market allocations. Guided by the model, we estimate that platform adoption is worth 77% of clients‘ pre-adoption profits from primary-market allocations. Overall, the effects of platforms in OTC markets are more complex than previously thought.
  
   

• November 12, 2026 / 12:00–13:00 / room tba
  Emanuele Rizzo (ESADE Business School)
  
   

• November 5, 2026 / 10:00-11:00 / D2.0.342
  Tobin Hanspal (Vienna University of Economics and Business) 
  Rebuying the Dip
  
  Abstract: Retail investor behavior is commonly associated with both momentum trading and contrarian `buying-the-dip' behavior, yet the literature offers little guidance on how these two patterns coexist. I show it depends on ownership. I use transactions and holdings from two German brokerages and a large U.S. discount broker to distinguish net-new purchases of stocks from additions to existing holdings. Conditional on buying, the same investor on the same day enters stocks with higher prior returns and adds to stocks with lower ones. Purchases after large daily gains disproportionately come from non-holders, whereas existing holders account for a larger share after price declines. The effect attenuates for funds and ETFs. Rebalancing toward past portfolio weights does not explain investors’ propensity to add to positions below cost basis. My findings imply that the buying response of retail investors to recent returns depends on ownership composition and investors' purchase history.
  
   

• November 4, 2026 / 11:45-12:45 / D4.4.008
  Pan Yiming (Vienna University of Economics and Business) 
  Short Sale Constraints and the Return Predictability of Idiosyncratic Variance: Evidence from Crypto Perpetuals
  (joint with Jia Zhai, Xi’an Jiaotong Liverpool University)
  
  Abstract: Why does idiosyncratic variance predict low returns? We study cryptocurrencies, where access to short selling expanded coin by coin. Upside idiosyncratic variance predicts low next day returns primarily among coins that cannot be shorted. This predictability comes from large idiosyncratic price moves of either sign, with recent shocks contributing more than older ones. Prices subsequently reverse after upside shocks and continue falling after downside shocks. Within the same coin, access to short selling reduces the week long reversal after upside shocks by 2.5 percentage points, about three quarters of its average magnitude. The evidence is consistent with short sale constraints delaying price adjustment, so that idiosyncratic variance predicts low returns because it records recent shocks whose adjustment remains incomplete.