This paper examines how sponsored search auctions shape product market competition. I develop a model in which firms bid for prominence on a platform and set prices, under a cost-per-click commission model. Consumers observe prices before search but incur costs to learn match values. The analysis reveals a novel mechanism: ad commissions pass through asymmetrically to prices. For the prominent firm, commissions function like a fixed cost, leaving its price largely unaffected; for the non-prominent firm, they act as a marginal cost, raising its price. This asymmetry reduces competition and can even reverse price rankings. I explore alternative commission models and provide suggestive empirical evidence consistent with the theory.

 Do constituents limit interest groups' influence over elected officials? Using new data on congressional speeches, campaign donations, and over 10 million lobbying contacts from FARA filings, we track politicians’ responses to international events that raise the political cost of appearing too close to foreign governments. We find three main results. First, politicians strongly connected to shocked countries lose local campaign contributions after a shock. Second, they are less willing than weakly connected politicians to praise the affected country in their speeches. Third, while weakly connected politicians increase in-person meetings with the lobbyists of shocked countries, strongly connected ones shift to remote contacts. We show that a simple relational contracting model can explain these findings. Overall, our study suggests that politicians' concern with their constituents' reaction can deter foreign influence—but only partially. Politicians and interest groups adjust to reputational shocks, forming new ties and reshaping old ones to navigate public scrutiny.

 Using Indian microdata on employer-employee caste composition and household consumption, we document demand segmentation along caste lines, limiting firms' market penetration and reducing firm size in the economy. We develop a model where consumers prefer goods produced by socially closer groups, and firms overcome these barriers by hiring employees from the target consumer group. We identify the structural parameters governing demand segmentation using rainfall-induced demand shocks. Counterfactuals indicate that social identity-driven barriers restrict the growth of high-quality firms while sustaining low-quality ones. Lowering the cost of hiring out-group employees expands firm size by improving market access and enhances consumer welfare through greater variety of products.

 Tanto en EE. UU. como en España, la publicidad online ya supuso en 2021 más del 50 por 100 del gasto total en publicidad. Unido a múltiples retos ya conocidos por los economistas (barreras de entrada por economías de escala, switching costs, efectos de red), la publicidad online añade además la personalización de la publicidad y las dificultades para preservar la privacidad. Veremos que la publicidad online potencialmente puede tanto favorecer como dificultar la competencia. Repasaremos literatura académica que ofrece claves para identificar y cuantificar formas en que la publicidad online puede generar barreras a la competencia y daños a los consumidores.

 - Watch: Shoplifters, (2018) - Japan
   - Read: The Paper Menagerie, by Ken Liu

 - night comes first (ongoing): முதலில் இரவு வரும் - ஆதவன், 1985 (Tamil)