An abbreviation for odd-lot balance index; a market sentiment indicator that relates odd-lot sales to odd lot purchases:

OLBI = 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 OLBI indicates 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.