A fractional share is a stock unit that is less than a whole share. Stock splits, bonus shares, and other corporate acts can result in fractional shares. Fractional shares aren't traded on stock exchanges, thus they can't be bought or sold there.

For Example –
If you own 9 shares of ABC Ltd, and the firm announces a 3 for 2 stock split, you will receive 3 shares for every two stocks you own. As a result, for the 9 shares you currently own, you are entitled to 4.5 more shares. Your total number of shares would be 13.5 after getting the 4.5 shares.

When fractional shares arise, most firms choose to round up to the next whole number of shares. ABC Ltd can choose to round up 0.5 shares and leave you with 14 shares in this situation.

When a company merges with another company, the shares held by shareholders are not identical to the share swap (i.e. exchange) ratio established for the merger.

Consider the following scenario:

Assume you own 29 shares of ABC Ltd, which recently merged, and the new business (XYZ Ltd) makes an offer to provide XYZ stock in a proportion of one stock for every five stocks you own (1:5). In this situation, you can only purchase 5 shares of the new firm XYZ (5*5 = 25), but the remaining 4 shares of the old company ABC are still available (29-25). You will be entitled for a fractional share in XYZ worth 0.8 (4 shares / 5 = 0.8) in this situation."
Is it possible to sell fractional shares?

Because fractional shares do not trade on exchanges, the corporation chooses a trustee to purchase them. The trustee then purchases the fractional shares from the investors and credits the proceeds to the primary bank account.