The Microcap Minute Classroom. Module 8, chapter 5: Index adds and drops: the forced buying and selling nobody sees <div class="learn" markdown="1"> **What you will learn** - What an index is, and what an index fund must do - Why joining a famous index creates forced buying - Why being dropped creates forced selling - Why this explains strange price moves but rarely makes easy money </div> Imagine the school announces the final eleven for the district team, and every cricket shop in town must stock exactly those eleven jerseys. The day the list changes, shops rush to buy the new player's jersey and dump the dropped player's, whatever the price. Nobody asks whether the players are any good. The rule book says buy. An index is a list of companies used to measure the market. The most famous American one, the S&P 500, holds 500 large companies chosen by a committee. An index fund is a giant pool of money that simply buys whatever is on the list, in the same proportions. These funds hold trillions of dollars (lakh upon lakh of crores of rupees). So when the committee adds a company, every fund tracking that list must buy it by the deadline. When a company is dropped, every fund must sell it. This has nothing to do with what the company is worth. It is plumbing. ## A worked example: Tesla joins the S&P 500 In November 2020 the committee announced that Tesla would join the S&P 500 just before Christmas. Tesla was already so large that index funds had to buy roughly $80 billion of its shares in a few weeks (about Rs 6.6 lakh crore): the biggest forced purchase in the index's history. Between the announcement and the day it joined, Tesla's price rose about 70%, partly on excitement and partly because everyone could see the forced buying coming. The much smaller company removed to make room was sold by the same funds on the same day, barely noticed. Notice you can sort and filter every US company by size: the border between "in the index" and "out of the index" runs right through a table like this. ## How to see it in the filings Every large US fund must report its holdings four times a year on a form called 13F, within 45 days of each quarter's end. After a big index change, thousands of 13F filings suddenly show the same new name. That is the paper shadow of forced buying. Notice the plain columns: company, shares held, value. Berkshire is not an index fund, but this is exactly the form every big fund files. Now the honest part, with numbers. In the old studies, a stock added to the S&P 500 jumped about 3% when the news broke, and nearly all of that jump faded within two weeks. So traders learned to buy the moment a change was even guessed at. The newest big study, watching companies promoted into the index from 2016 to 2020, found the effect had flipped upside down: added stocks fell about 2.5% on average in the three days around the announcement, and dropped stocks rose about 1.4%. Everyone rushed in so early that the announcement itself became a place to sell. That makes this chapter the weakest money-making signal in the module, even though the machinery is real. A dropped company still faces mechanical selling, and the same plumbing explains why small spin-offs wobble in their first days. By the time you and I read the news, the move is done. Your real gain is understanding: when a quiet company jumps 8% on no news, or a dropped name sinks while its business is fine, you will know which invisible hand moved it, and you will not mistake plumbing for a verdict on the business. <div class="try" markdown="1"> **Try it yourself** (10 minutes): open the [S&P 500 list on StockAnalysis](https://stockanalysis.com/list/sp-500-stocks/?ref=MICROCAPMINUTE) and sort it by market value. Scroll to the bottom: the smallest members live closest to the trapdoor. Then search the news for the most recent S&P 500 change and note what the added and dropped shares did in the days around it. </div> <div class="takeaways" markdown="1"> **Key takeaways** - An index is a fixed list; index funds must buy and sell exactly what the list says. - Joining the S&P 500 creates enormous forced buying; being dropped creates forced selling. But the old buy-the-news trick has flipped: from 2016 to 2020, additions fell 2.5% on average around the announcement. - These moves say nothing about what the business is worth. - Form 13F lets you watch big funds' holdings change every quarter. - Use this knowledge to explain strange price moves, not to chase them. </div>. I am Ritu, a synthetic voice, and the words I am reading are Ayush Agrawal's.

# Index adds and drops: the forced buying and selling nobody sees <div class="learn" markdown="1"> **What you will learn** - What an index is, and what an index fund must do - Why joining a famous index creates forced buying - Why being dropped creates forced selling - Why this explains strange price moves but rarely makes easy money </div> Imagine the school announces the final eleven for the district team, and every cricket shop in town must stock exactly those eleven jerseys. The day the list changes, shops rush to buy the new player's jersey and dump the dropped player's, whatever the price. Nobody asks whether the players are any good. The rule book says buy. An index is a list of companies used to measure the market. The most famous American one, the S&P 500, holds 500 large companies chosen by a committee. An index fund is a giant pool of money that simply buys whatever is on the list, in the same proportions. These funds hold trillions of dollars (lakh upon lakh of crores of rupees). So when the committee adds a company, every fund tracking that list must buy it by the deadline. When a company is dropped, every fund must sell it. This has nothing to do with what the company is worth. It is plumbing. ## A worked example: Tesla joins the S&P 500 In November 2020 the committee announced that Tesla would join the S&P 500 just before Christmas. Tesla was already so large that index funds had to buy roughly $80 billion of its shares in a few weeks (about Rs 6.6 lakh crore): the biggest forced purchase in the index's history. Between the announcement and the day it joined, Tesla's price rose about 70%, partly on excitement and partly because everyone could see the forced buying coming. The much smaller company removed to make room was sold by the same funds on the same day, barely noticed. Notice you can sort and filter every US company by size: the border between "in the index" and "out of the index" runs right through a table like this. ## How to see it in the filings Every large US fund must report its holdings four times a year on a form called 13F, within 45 days of each quarter's end. After a big index change, thousands of 13F filings suddenly show the same new name. That is the paper shadow of forced buying. Notice the plain columns: company, shares held, value. Berkshire is not an index fund, but this is exactly the form every big fund files. Now the honest part, with numbers. In the old studies, a stock added to the S&P 500 jumped about 3% when the news broke, and nearly all of that jump faded within two weeks. So traders learned to buy the moment a change was even guessed at. The newest big study, watching companies promoted into the index from 2016 to 2020, found the effect had flipped upside down: added stocks fell about 2.5% on average in the three days around the announcement, and dropped stocks rose about 1.4%. Everyone rushed in so early that the announcement itself became a place to sell. That makes this chapter the weakest money-making signal in the module, even though the machinery is real. A dropped company still faces mechanical selling, and the same plumbing explains why small spin-offs wobble in their first days. By the time you and I read the news, the move is done. Your real gain is understanding: when a quiet company jumps 8% on no news, or a dropped name sinks while its business is fine, you will know which invisible hand moved it, and you will not mistake plumbing for a verdict on the business. <div class="try" markdown="1"> **Try it yourself** (10 minutes): open the [S&P 500 list on StockAnalysis](https://stockanalysis.com/list/sp-500-stocks/?ref=MICROCAPMINUTE) and sort it by market value. Scroll to the bottom: the smallest members live closest to the trapdoor. Then search the news for the most recent S&P 500 change and note what the added and dropped shares did in the days around it. </div> <div class="takeaways" markdown="1"> **Key takeaways** - An index is a fixed list; index funds must buy and sell exactly what the list says. - Joining the S&P 500 creates enormous forced buying; being dropped creates forced selling. But the old buy-the-news trick has flipped: from 2016 to 2020, additions fell 2.5% on average around the announcement. - These moves say nothing about what the business is worth. - Form 13F lets you watch big funds' holdings change every quarter. - Use this knowledge to explain strange price moves, not to chase them. </div>

That was chapter 5 of module 8. The text, the pictures and the exercise are on the lesson page. Thank you for listening.