Friday, May 12, 2017

Arbitrage trades and their impact on spot market pricing

Here is the textbook definition of how Arbitrage Funds earn money: “Arbitrage fund leverages the price differential in the cash and derivatives market to generate returns. The fund simultaneously buy shares in the cash segment and sell futures in the derivatives segment of the same company as long as the futures are trading at a reasonable premium.”

This would mean they do no-risk trades. Though there would be transactions costs (may be taxes as well), this arbitrage would still generate positive return with a very high probability. This opportunity exists as long as premiums on futures remain high creating a spread between spot price and its futures.

First we need to ask why there is a premium on the futures. Because there is a hope that underlying stock would gain, buyers of Futures are willing to pay a premium. But at the expiry, hope meets reality and the spot price converges with futures price resulting the premium to become zero. This cycle repeats every month.

Beginning of the new series as the premium is high, these funds enter the trade and when there is no premium to earn (at expiry or before), these trades end with square-off in futures and selling in cash market. They would earn at least 1-2% month per trade.

It is good for Arbitrage funds. But for rest of the traders, these trades might give false impressions of what is happening. As those funds buy in the sport market, demand goes up so will be the spot price. But they are creating a short position in futures market simultaneously. When they want to square-off the derivative they hold, they sell in spot market which causes pressure and the spot price declines. So this creates a price range and within that a stock would move multiple times.

You might think all of the trades in the spot market are not arbitrage trades. Looking at the data shows that majority of the trades are indeed done by these arbitrage funds. They contribute significantly to the volume. Take example of IDFC Bank stock. The number of shares owned by Arbitrage funds in this stock is a lot higher than long term mutual funds hold and also higher than its daily or monthly average trade volume in the spot market. These funds are not long term investors but only interested in pocketing the premium and they do not care about the underlying direction of the stock. Since they would win anyway, they do not shy to create a stampede while selling or would not mind to create a hysteric demand taking the price up and increasing the arbitrage opportunities for themselves.

When they are buying, price levels see an increase beyond what it would be possible if these arbitrage funds were not present. Once their trades are set, they stop buying and the price drops as demand drops too. At this stage, arbitrage funds might decide buying again increasing the Open Interest levels or they can square-off exiting spot market too. And in the process they would damage the price to an extent of 1% to 10% depending on the depth of the market. But the fall won't be forever as they need to create hope for buyers to pay a premium which would happen with fresh buying. That is to sell futures at higher premium. This cycle repeats at least once a month and sometimes more within a month.

When a stock (traded in F&O) sees a sharp up move and then just passes time for the rest of the month, you know now who profits from it. Now that we are aware of their presence, how do we get to know their actions and how we can profit from it? I would write about that in a future blog post.