See impt paper by Nocke and Wilson arguing that the key is the increase in concentration. Consistent with PhillyBank: a merger producing both a significant market share and "a significant increase in the concentration of firms." 374 U.S. at 363. https:…
@alz_zyd_ Related https://t.co/mNEPSxFMEH
@JosephVConiglio @matthewstoller @BilalKSayyed One important takeaway from this piece is that the ΔHHI is an important metric -- few cause harm when the ΔHHI<100. That's also the conclusion in Nocke/Whinston, linked below, which find a strong inverse …
RT @k_ryukius: Nocke and Whinston (2022, AER)、今日の授業で先生が紹介した論文。合併審査の閾値として使われるものの、理論的裏付けがなかったHHIの増分について理論・実証両面で分析。合併後におけるHHIの水準よりむしろHHIの増分の方が…