"Den 25:e smäller det!" Payday Arbitrage in Swedish Consumer Market Behavior

Abstract: This thesis investigates the impact of the Swedish salary disbursement schedule on consumer behavior, particularly on the 25th of each month, a notable payday for most employees in Sweden. The study examines whether the anticipation of a monthly salary influences consumer decisions and spending patterns, potentially leading to payday-related arbitrage opportunities in Swedish marketplaces. By scrutinizing transaction data from Tradera, this research seeks to reveal if there is a discernible fluctuation in prices that corresponds with the inflow of regular salaries. Our analysis uncovers a modest but statistically significant increase in bidding activity post-payday, with a 2% rise in prices and a notable increase in bid volumes. However, this effect does not translate into substantial arbitrage opportunities due to the platform's fee structure and shipping costs. Intriguingly, day-of-the-week patterns emerged as more influential in shaping bidding behavior than payday effects. These findings contribute to the understanding of consumer market dynamics in response to synchronized salary disbursements, enriching the discourse on behavioral finance and auction theory.