Help Determine Wash Sale-Bought and Then Sold the Same Lot within a Month (United States)

External question — Personal Finance Stack Exchange Author: user108025 Original post: https://money.stackexchange.com/questions/139193 License: CC BY-SA 4.0 — https://creativecommons.org/licenses/by-sa/4.0/ Adaptation: HTML converted to plain text; contact email addresses removed. I did research on the previous posts but could not find an answer that matches my exact situation. I understand IRS definition of wash sale occurs when you sell or trade stock or securities at a loss and within 30 days before or after the sale you buy substantially identical stock or securities, and the identical stock shares purchased is the "replacement" for the shares you sold. However, I am struggling to figure out if the below situation is considered a wash sale. Activity 1: Bought 80 shares at $250/share on 1/28 (Lot A); Activity 2: Bought 90 shares at $200/share on 2/17 (Lot B); Activity 3: Sold 90 shares at $190/share on 2/18 (Lot B); Within one month before the sale of 90 shares, there are two purchases. However, the purchase Activity 2 (Lot B) was completely sold the next day (Activity 3), and my purpose of purchase Activity 1 was not to replace the shares I sold in Activity 3 as it was a different lot purchased before the lot I sold. Is this still considered a wash sale? If so, should I take the capital loss for 10 shares in Lot B and raise the cost basis of the 80 shares in Lot A? Thanks in advance for the help!