Is Eli Lilly Stock a Good Fit For Your Portfolio Risk?

You may own Eli Lilly (LLY), a drugmaker worth about $1.05 trillion, beside funds that already track the S&P 500. A single stock can become a big part of your money, so its daily moves matter for all of it. Is Eli Lilly stock a good fit for the risk you already carry?

Partly: Eli Lilly Held Up On Average Down Days

Over the past year of daily closes, Lilly followed the market’s daily moves only weakly. On the average day the S&P 500 rose, the index gained 0.63% and Lilly gained 0.35%. On a $10,000 holding, that was about $35.

On the average day the index fell, it lost 0.61%. Lilly still edged up 0.08% on those days. That was a gain of about $8 on $10,000.

Lilly moved about 0.34% for each 1% move in the S&P 500 over the same year. By that measure, Lilly adds little to the market risk you already hold.

Lilly’s own swings are much wider, though. Volatility measures how widely a price moves up and down over a year. Lilly’s was 36% over the past year, against 13.0% for the S&P 500.

Lilly can also fall hard in a bad month for the market. March 2026 was the index’s worst month of the past year. The S&P 500 fell 5.1% that month, and Lilly fell 12.6%. On $10,000 of Lilly stock, March cost about $1,257. So Lilly lowers the risk from the market’s ordinary days, but it brings large swings of its own.

Eli Lilly Out-Earned The Index Per Unit Of Volatility

Over the past five years, Lilly returned 40% a year including dividends, against 13.6% for the S&P 500.

You can divide that annual return by the annual volatility over the same five years, which was 32.7% for Lilly and 17.0% for the S&P 500. The result is the return earned for each unit of swing. Over the five years, Lilly’s figure was 1.22, against 0.8 for the S&P 500. So you were paid more for each unit of Lilly’s swing than for each unit of the market’s.

Will Eli Lilly Stay This Independent Of The Index?

Lilly depends heavily on two drugs and faces big tests ahead. Over the past year, Lilly’s daily moves had little to do with the market’s. Their correlation, where 1 means the two always move together, was 0.13.

Lilly made $14.9 billion from Mounjaro and Zepbound in the second quarter of 2026. The two are its diabetes and obesity drugs. That was about two-thirds of its $23.0 billion in revenue for the quarter.

On the second-quarter 2026 call, management said Zepbound’s price will fall as access widens. Lilly is also building on the spring 2026 FDA approval of Foundayo (orforglipron) for weight management as it awaits regulatory decisions to expand its label for type 2 diabetes. So Lilly’s shares are likely to keep moving on the company’s own news.

Over the past five years, you were paid well for Lilly’s swings. If Lilly cannot make up for lower Zepbound prices with higher sales volume, the pay for those swings would be in doubt.

If the past year repeats, Lilly will tend to rise less than your index funds on an average up day. On an ordinary down day, Lilly would tend to hold steady and soften the loss on your whole portfolio. Lilly can still fall hard in a bad month for the market. If you already own another maker of obesity drugs, Lilly would add to that bet rather than spread your risk.

Beyond LLY: A Systematic Way To Grow Your Money

Before you decide on LLY, consider a better choice. Since its inception, the Trefis High Quality (HQ) Portfolio has returned 105%, beating the benchmark that combines the three major indices – the S&P 500, S&P Mid-cap, and Russell 2000. And it did so without taking concentrated risk that comes with do-it-yourself stock picking.