A market sentiment indicator that relates odd-lot sales to odd lot purchases:

Odd-lot balance index = odd-lot sales / odd-lot purchases

An odd lot is a transaction in which less than 100 share units are traded. Odd lotters are the smallest traders in a stock market. They are assumed to be unaware of the actual market direction and timing and therefore they don’t know their course of action. High odd-lot balance index (OLBI) values indicate that odd lotters are selling more than they are buyer (or odd-lot sellers outnumber odd-lot buyers). In this case, odd lotters are said to be bearish on the market. Low OLBI suggests that the number of odd-lot buyers exceeds the number of odd-lot sellers. Therefore, odd lotters are considered bullish on the market.