Example of cash in lieu
Let's say you purchased 105 shares of a company's stock at $50 per share. Your total cost basis is $5,250. The company announces a 3-for-2 stock split, meaning you'd be due an additional 52.5 shares after the split, bringing your total number of shares to 157.5.
If the company doesn't want to issue fractional shares, it would distribute 52 additional shares and cash in lieu of the fractional share. Because of the stock split, your per-share cost basis would drop to $33.33. You can calculate this by dividing the total number of shares you'd have after the split, 157.5, by your total cost basis of $5,250. If the half-share was sold at a share price of $38, then you'd have capital gains of $4.67.