Have I got a deal for you: stock prices ending in nine

Bagnoli, Park and Watts, Nines in the Endings of Stock Prices, provide nifty evidence that this isn't the same thing as retail prices ending in nine:

Retail prices that end in nine are often associated with an increase in demand, consistent with customers perceiving the presence of a small discount or underestimating the price. In this paper, we ask whether investors respond similarly to stocks with nines in the rightmost digits of their prices. In contrast to what is observed in retail settings, excessive overnight selling follows stocks that close on 9-ending prices. Additional analysis indicates this may be due to a resistance level created by round-dollar prices. Thus, in stock market settings, just missing a round-number benchmark is likely to be associated with dampened, rather than stimulated, demand.