On which date does the settlement occur when stock is purchased on September 15?

When a stock is purchased, the standard settlement date for most securities is two business days after the trade date. This is known as T+2 (Trade date plus two days).

In this scenario, the stock is purchased on September 15. The first business day after this date is September 16, and the second business day is September 17. Therefore, the settlement for the stock purchase will occur on September 17.

This follows the industry practice for clearing and settling stock transactions, ensuring that the buyer has that amount of time to provide payment and the seller to deliver the stock. Thus, September 17 is the correct date for settlement in this context.