January effect

In the US, investors sell losing stocks near the end of the year. The reason is tax: booking the loss reduces their tax bill. They then buy the same stocks, or similar ones, back after the new year.

All that selling lands in the same few weeks. It puts downward pressure on prices in late November and December. The buying back puts upward pressure on prices in early January.

Other investors noticed. They buy the beaten-down stocks in December and sell them higher in January.

That repeating pattern is the January effect. It matters because it should not exist. In an efficient market, a price pattern everybody can see would be traded away.

So the workbook files it as a market anomaly — evidence against the efficient market hypothesis.

The mechanism (section 13.4.1). In the US market it is observed that investors tend to engage in tax selling towards the end of the year to book losses on stocks that have declined, and then buy back the same stocks or similar stocks after the new year. This leads to downward pressure on stock prices towards the end of November and December, and positive pressure in early January. Other investors take advantage of the tax selling by acquiring stocks at lower prices in December and selling them at higher prices in January. Such price patterns are inconsistent with the EMH.

The regulatory answer. The workbook records that the US Internal Revenue Service enacted the Wash Sale Regulation, preventing an investor from taking a tax deduction for selling securities using anomalies like this. Its footnote defines a wash sale as selling or trading securities at a loss and, within 30 days before or after the sale, buying substantially identical securities, acquiring them in a fully taxable trade, or acquiring a contract or option to buy them.

Where it sits. Section 13.4 lists three anomalies — the January effect, the size anomaly and the value anomaly. The workbook's framing is that such anomalies led to the development of popular investment strategies, and that active portfolio managers use them to derive alpha.

No Indian figure and no Indian rule. Section 13.4.1 locates the effect in the US market and cites only the US wash sale rule. The workbook gives no data for Indian markets, no measured size for the effect in percentage terms, and no Indian equivalent of the wash sale regulation. The only number attached to the topic anywhere in the section is the 30-day window in the wash sale footnote.

The research citation. The workbook attributes the tax-loss trading rule to Ben Branch, A Tax Loss Trading Rule, The Journal of Business, 1977.

Illustrative figures. The workbook locates the January effect in the US market and gives no measurement of it; the rupee arithmetic below shows the mechanism at work so the size of the pattern is visible.

A trader watches a stock that has fallen from Rs 400 to Rs 250 over the year. Loss-booking sellers push it to Rs 235 by the third week of December.

He buys 8,000 shares at Rs 235 = Rs 18,80,000.

In the first fortnight of the new year the sellers return as buyers and the price recovers to Rs 262. He sells:

• Proceeds: 8,000 x Rs 262 = Rs 20,96,000
• Gain: Rs 2,16,000, or 11.5% in about three weeks

He took no view on the company's business at all. His only input was the calendar and the tax behaviour of other people.

Now look at the seller's side. She sold 8,000 shares at Rs 235 to book a loss of Rs 165 a share, that is Rs 13,20,000 of loss, so as to set it against gains elsewhere. If she buys back in January at Rs 262, she has paid Rs 2,16,000 more than she received to end up holding the same stock. Whether that was worth doing depends entirely on the tax saved — and a wash sale rule of the American kind is designed to stop the deduction being available at all.

Chapter 13 (Concept of Informational Efficiency), section 13.4.1, is the first of the three anomalies the workbook lists, and its sample question 3 asks it almost verbatim: the opportunity to take advantage of the downward pressure on stock prices that results from end-of-the-year tax selling is known as — with the answer being the January anomaly.

Expect that question, a question on why an anomaly contradicts the EMH, and one grouping the three anomalies together. The wash sale connection is tested from the other side, as the regulation that blocks the tax deduction.

• The selling happens in November and December; the rise happens in January. The anomaly is named after the upswing, not the pressure that causes it. Reading it as December selling only loses half the mechanism.
• This is a US observation with a US tax cause. The workbook gives no Indian data and no Indian wash sale rule, so do not answer that the same pattern is documented for the NSE.
• The wash sale window is 30 days before or after the sale. Both sides, not just the repurchase side.
• An anomaly is evidence against efficiency, not proof of it. The workbook is careful that the evidence on the EMH is mixed — some studies support it, others reveal anomalies.
• It is a calendar anomaly, not a size or value one. The size anomaly is about small firms outperforming; the value anomaly is about high book-to-price stocks. Three separate findings in one section.