Marvell Technology’s S&P 500 Invitation
Marvell Technology (MRVL) jumped around 13% on Monday after receiving an invitation to join the S&P 500 index. This kind of announcement typically prompts index funds to make purchases, which often leads traders to jump in ahead of those funds.
However, this situation can present a tricky pattern. A review by Yahoo Finance of 1,926 stocks added to the S&P 500 since 1957 found that these stocks usually perform well before their actual inclusion in the index but tend to underperform afterward.
For funds that track the S&P 500, acquiring new members is a fundamental task. Index funds are naturally inclined to pick up these stocks, while hedge funds may try to second-guess when to buy. It turns out these added stocks often see a good performance boost before they actually join the index.
Specifically for firms like Marvell, they have shown a median stock price that outperformed the S&P 500 by 3.3% during the 25 trading days leading up to their index debut.
This historical context raises concerns about Marvell’s future performance. The data suggests that the most noticeable advantages linked to index inclusion tend to manifest before the actual entry. Marvell has already captured significant momentum, with nearly two weeks left until its official inclusion on June 22.
After that date, things can shift dramatically. The stock’s dynamics often change once it officially joins the index.
It’s important to note that the chart doesn’t indicate that new additions are necessarily losing money; rather, it evaluates performance against the S&P 500. For example, the median addition was approximately 1% below the index at the one-quarter mark, about 2% lower after two quarters, and roughly 8% down after a year. Almost 60% of stocks added tended to underperform compared to the S&P 500 after one year.
The trends have evolved over time. Prior to 1990, new inclusions to the S&P 500 were uncommon, according to Yahoo Finance. From 1990 through 2009, the power of index inclusion strengthened. Passive investing has indeed surged, increasing demand for index-related stocks in the market.
Since 2010, this influence hasn’t faded. As trade activity increased, hedge funds and other investors felt more inclined to speculate on upcoming index rebalancing, thereby ramping up buying pressure leading up to these events.
That said, not every stock’s index inclusion spells disaster. For instance, Palantir (PLTR) saw a significant rally, while Super Microcomputer (SMCI), Netflix (NFLX), and Penn Entertainment (PENN) showed that strong fundamentals can sometimes overshadow initial effects of joining the index.
This presents a crucial challenge for Marvell. The invitation to join the S&P 500 could stimulate interest right up to the June 22 entry date. The real test will come after that—will the initial excitement be just a fleeting bump or the start of something more lasting?
