If you were looking for a new restaurant to try out, a famous chef's recommendation would probably carry a lot of weight. If you wanted to find an up-and-coming singer to listen to, you'd likely check out an artist that a legendary musician suggested.

But what if you're looking for stocks to buy? Maybe you could find out which stocks a well-known company that has been successful for a long time really likes -- a company such as Johnson & Johnson (JNJ -0.46%). The good news is that we only have to look at the healthcare giant's 13F regulatory filings. Here are the three stocks that J&J is betting the most on.

1. Legend Biotech

As of Sept. 30, 2023, Johnson & Johnson's biggest investment was in Legend Biotech (LEGN 1.98%). J&J's stake in the small biopharmaceutical company was worth more than $54.7 million.

In 2017, Johnson & Johnson teamed up with Legend to develop a chimeric antigen receptor T-cell (CAR-T) candidate called LCAR-B38M. J&J received a worldwide license to jointly develop and market the CAR-T therapy with Legend for an upfront payment of $350 million plus contingent milestone payments.

The collaboration appears to be on track to pay off nicely. LCAR-B38M (now known as Carvykti) won U.S. Food and Drug Administration (FDA) approval for treating multiple myeloma after four or more prior lines of therapy in 2022. J&J and Legend await an approval decision on the therapy as a second-line treatment of multiple melanoma after reporting overwhelmingly positive results from a phase 3 study earlier this year.

Johnson & Johnson isn't the only big pharma company that Legend Biotech has attracted. Only a few days ago, Legend announced a deal to license some of its other CAR-T programs, including LB2102, to Novartis for an upfront payment of $100 million plus potential milestone payments of up to $1.01 billion.

2. CVRx

CVRx (CVRX 2.08%) comes in close behind Legend Biotech in Johnson & Johnson's investment portfolio. At the end of September, J&J's position in CVRx was worth a little over $53 million.

Unlike Legend Biotech, CVRx isn't a drugmaker. The company develops and markets heart failure devices. Its Barostim system is the first FDA-approved medical device that uses neuromodulation (electrical stimulation of neurons) to help patients with heart failure.

Johnson & Johnson's ties with CVRx date back to 2008 when it first invested in the medical device maker. In 2016, J&J's venture capital unit led the way in a Series G round of financing for CVRx.

CVRx conducted its initial public offering (IPO) in July 2021. The medical device stock didn't get off to a great start, plunging more than 80% over the next 12 months. However, CVRx's share price has tripled since mid-2022.

3. Protagonist Therapeutics

Johnson & Johnson's third-largest holding is Protagonist Therapeutics (PTGX 1.99%). As of the close of the third quarter of 2023, the big healthcare company owned nearly 2.45 million shares of Protagonist that were worth over $40.8 million.

Protagonist first attracted interest from Johnson & Johnson back in 2013 in the small biotech's Series B round of financing. J&J also participated in Protagonist's Series C round.

In 2017, the two companies announced a licensing and collaboration agreement for Protagonist's interleukin-23 receptor antagonist candidate PN-235. J&J announced positive results earlier this year from a phase 2b study evaluating the experimental therapy, now known as JNJ-2113, in treating plaque psoriasis. JNJ-2113 is also in clinical studies targeting psoriasis and ulcerative colitis.

Protagonist also has another pipeline candidate for which it owns full rights. The company is evaluating rusfertide (PTG-300) in a late-stage clinical study targeting the treatment of rare blood disorder polycythemia vera.

Should you follow in J&J's footsteps?

No one should buy any of these three stocks just because Johnson & Johnson owns stakes in them. For one thing, biotech and medical device stocks aren't great fits for every investor.

Of these three J&J holdings, I think that Protagonist Therapeutics appears to be the most promising. Should JNJ-2113 deliver on its potential in treating multiple autoimmune diseases, Protagonist should be a big winner. However, there's no guarantee that the therapy will sail through its remaining clinical testing. Only aggressive investors who aren't afraid of taking on significant risks should consider this stock.