I examine how transparency and interdealer trading affects prices investors pay in municipal bond offerings. Real-time trade reporting for municipal bonds started January 31, 2005. The dispersion of purchase prices fell sharply at that time. There was little impact on average markups for most trades, but they increased for purchases of more than $100,000. Bonds often pass through a series of dealers before being placed with a buy-and-hold investor. As the interdealer trades progress, trade sizes decline and trade prices rise. Markups on investor purchases increase with the amount of interdealer trading before the trade.

ABSTRACT We develop a bid‐ask spread estimator from daily high and low prices. Daily high (low) prices are almost always buy (sell) trades. Hence, the high–low ratio reflects both the stock's variance and its bid‐ask spread. Although the variance component of the high–low ratio is proportional to the return interval, the spread component is not. This allows us to derive a spread estimator as a function of high–low ratios over 1‐day and 2‐day intervals. The estimator is easy to calculate, can be applied in a variety of research areas, and generally outperforms other low‐frequency estimators.