Wash Sale

This is a US rule, not Indian tax law. The workbook brings it up only to explain one thing: why the January Effect anomaly is not a completely free lunch for American investors.

The January Effect is a seasonal pattern. The workbook places it specifically in the US market. Investors sell losing stocks in November and December to book a tax loss. That selling pushes prices down. Then, in January, they buy the same or similar stocks back. That buying pushes prices back up.

The US wash sale rule is the anti-abuse provision built to stop investors exploiting that pattern too cleanly for tax purposes.

The workbook's footnote, in full: "A wash sale occurs when one sells or trades securities at a loss and within 30 days before or after the sale she/he: Buys substantially identical securities, Acquires substantially identical securities in a fully taxable trade, or Acquires a contract or option to buy substantially identical securities. Internal Revenue Service rules prohibit deducting losses related to wash sales."

The key number is 30 days, and it runs in both directions — 30 days before the sale as well as 30 days after it, so an investor cannot dodge the rule by buying the replacement shares slightly early. The rule disallows the tax-loss deduction; it does not stop the trade itself. An investor can still sell and rebuy within the window — they simply cannot claim the loss against their US tax liability for having done so.

The workbook's own illustration is American, not Indian: an investor holds a technology stock bought at $80, now trading at $60 in December — an unrealised loss of $20 a share. Selling 500 shares on 20 December books a realised loss of $10,000 for the current US tax year, and the investor intends to buy the same stock back once the new year starts.

On 5 January, the investor buys back 500 shares of the same stock. Because the repurchase falls within the 30-day window and the shares are substantially identical to the ones sold, the IRS wash sale rule disallows the $10,000 loss deduction for that tax year. Multiply this investor by thousands of others doing the same thing in the last weeks of December, and the pattern is exactly what the workbook's January Effect section describes: selling pressure into the year-end and a rebound in January — a seasonal pattern the workbook says is inconsistent with market efficiency, even though the wash sale rule limits its tax benefit.

Chapter 13, section 13.4.1 (The January Effect), cites the wash sale rule as the US IRS's response to year-end tax-loss trading. Expect it tested as a footnote-level fact tied to the January Effect, and as a check on whether the candidate correctly identifies it as US law with no Indian statutory equivalent taught in this workbook.

• This is a US Internal Revenue Service rule, not an Indian Income-tax Act provision. Do not apply it to an Indian capital-gains tax question — the workbook gives no equivalent Indian rule.
• The 30-day window runs both before and after the sale — a 60-day total exposure — not just 30 days after.
• The rule disallows the tax loss deduction; it does not prohibit the trade. An investor is free to sell and rebuy within the window; they just cannot claim the loss for tax purposes.
• The wash sale rule explains why the January Effect anomaly persists in a muted form rather than being fully arbitraged away by tax-motivated trading — it curbs the tax benefit of the pattern without eliminating the trading pattern itself.