Sometimes, when I want to buy a stock, I will spread the buying over several weeks in order to "cost average" the purchase price. This may involve buying in odd lots (i.e. the number of shares is not a multiple of 100). For example, buy 130 shares on day 1, 136 shares on day 2, 123 shares on day 3, etc. In the past, this practice had the disadvantage of higher transaction costs due to odd lot fees charged by US brokerages. Given that we are now in an era without odd lot fees, are there still any advantages of buying in round lots rather than odd lots?
There is not much of a difference. The only obstacle that might get in your way if a security is trading with low volume. Then, you will "get what you will get" . Example, if you buy 140 shares of stock, there may be a seller of 100 shares at X and another seller at Y. To avoid this, use limit orders for fills.