We study the influence of numerological superstitions on people’s buying behavior in the apartment market using unique actual sales data. Based on the dataset from Saint-Petersburg primary real estate market we compare the share of sold apartments on floor 7 with that on floors 6 and 8, whereas floor 13 is benchmarked to floors 12 and 14. As floor plans are absolutely identical we manage to isolate the effects of the “lucky” and “unlucky” floors. The data we use allows clean identification of superstition effects, while being publicly available. We have found a clear negative effect of the 13th floor on demand for apartments, and a significant effect of preference towards the 7th floor compared to the two neighboring floors. Possible applications of our approach to other areas of consumer research are discussed. % changed