Can You Make Money Off Halozyme Stock Now?
For questions about this article or underlying research, email help@trefis.com.
Halozyme Therapeutics (HALO) stock has fallen 21.5% from its October 29 high, most of it on November 6, the day after its third-quarter call. If you are tempted to buy, you are betting that the royalties Halozyme collects on its partners’ drugs keep growing and that its patents hold up against Merck. So how have buyers done after past Halozyme drops this deep?
How Much Did Buyers Of Past Halozyme Drops Make?
In the middle case, a $10,000 investment in Halozyme on the day of a past drop was worth about $13,150 a year later. Since 2010, the stock has recorded 21 falls of more than 20% in roughly six weeks. Sixteen of the 20 drops with enough history to evaluate left the shares higher a year later. The worst performer ended the year down 42% following the August 2015 drop, and the March 2026 drop is too recent to judge.
Collecting those gains usually meant sitting through a further fall. In the middle case, a $10,000 purchase was worth about $8,650 at its lowest close during the year after the drop. The stock reached its best price of that year after a median of 309 days, or about ten months.
| Time after a past dip | Past dips with that much time after them | Median HALO price change |
|---|---|---|
| 21 trading days | 21 | 7.0% |
| 63 trading days | 21 | 13.0% |
| 126 trading days | 21 | 17.0% |
| 252 trading days | 20 | 31.5% |
| Dip date | Change to dip date (HALO / SPY) | 1 year later | Best in that year (days to it) | Worst in that year |
|---|---|---|---|---|
| 2026-03-23 | -22.6% / -5.0% | – | – | – |
| 2025-06-20 | -24.7% / 6.0% | 35.0% | 53.8% (231 days) | -1.5% |
| 2025-05-13 | -21.3% / 5.0% | 37.0% | 61.7% (269 days) | -4.6% |
| 2024-10-25 | -20.9% / 3.0% | 31.0% | 58.9% (332 days) | -13.6% |
| 2023-03-10 | -21.9% / -5.0% | 1.0% | 5.8% (153 days) | -27.3% |
| 2022-09-02 | -21.4% / -1.0% | 5.0% | 52.7% (91 days) | -22.2% |
| 2021-06-03 | -20.5% / 1.0% | 18.0% | 24.4% (358 days) | -18.1% |
| 2021-03-08 | -20.2% / 0.0% | -12.0% | 29.9% (52 days) | -19.5% |
| 2020-03-17 | -21.8% / -22.0% | 196.0% | 242.5% (344 days) | -7.5% |
| 2016-12-28 | -28.3% / 4.0% | 109.0% | 109.9% (350 days) | -0.3% |
| 2016-10-28 | -26.9% / 0.0% | 101.0% | 103.9% (353 days) | -5.0% |
| 2016-06-03 | -20.1% / 1.0% | 32.0% | 52.4% (286 days) | -19.2% |
| 2016-01-11 | -29.9% / -8.0% | 4.0% | 15.1% (364 days) | -42.0% |
| 2015-08-20 | -23.3% / 0.0% | -42.0% | 12.4% (28 days) | -58.3% |
| 2014-12-15 | -20.3% / -1.0% | 107.0% | 222.7% (219 days) | -0.4% |
| 2014-03-07 | -21.3% / 3.0% | 11.0% | 13.5% (362 days) | -48.7% |
| 2013-02-22 | -20.5% / 4.0% | 172.0% | 197.3% (335 days) | -13.5% |
| 2012-11-06 | -31.6% / -2.0% | 111.0% | 124.7% (351 days) | -11.4% |
| 2012-08-02 | -52.1% / 1.0% | 65.0% | 101.9% (347 days) | 0.0% |
| 2012-04-16 | -24.2% / 0.0% | -35.0% | 14.3% (102 days) | -49.7% |
| 2010-05-20 | -23.3% / -9.0% | 0.0% | 28.0% (146 days) | -6.2% |
| Median of 20 complete years | – | 31.5% | 53.3% (309 days) | -13.5% |
Are Halozyme’s Royalties Still Growing?
They are so far. Royalty revenue rose 44% to a record $341 million in the third quarter, management said on the November 5 call. Halozyme collects these royalties when partners use its ENHANZE technology to convert intravenous drugs into shots under the skin. Management credited the performance to both established partner drugs and newer launches like OCREVUS ZUNOVO and OPDIVO Qvantig. On November 6, Halozyme announced that the FDA had granted accelerated approval to RYBREVANT FASPRO, a partner drug made with ENHANZE and already used in lung cancer, for advanced head and neck cancer. Management also raised its 2026 royalty forecast, which now projects growth of 42% to 45%.
Halozyme keeps much of what it collects. Over the past twelve months, the company retained 55.9% of revenue as operating profit, against 19.0% for the S&P 500. In the third quarter, its operations generated cash equal to 52.4% of revenue. Yet the shares trade at 13.0 times twelve-month operating cash flow, against 15.2 for the S&P 500. On twelve-month earnings, though, they trade at 24.1 times, against 22.3 for the index.
Where Halozyme’s Patent Fight With Merck Stands
Halozyme has won in Europe but not yet in the U.S. The dispute centers on whether Keytruda Qlex, Merck’s under-the-skin version of Keytruda, infringes Halozyme’s patent, and it drew investors’ attention after the call. Merck has also challenged whether that patent is valid. On October 7, 2026, a Dutch court found Keytruda Qlex infringing, rejected Merck’s claim that the patent is invalid, and barred it in eight European countries, after a German court ruling in December 2025 ordered Merck to halt its launch there. Management said that, in its experience with under-the-skin drugs, those markets, with Germany, make up about 20% of total global royalties.
In the U.S., where Halozyme’s patents are separate from the European one, Merck has won initial rulings against their validity. Halozyme is appealing, and management expects the appeal to run until 2028, saying it is very confident it will prevail. Patents matter to the royalties themselves: in one of its recent deal structures, management said, the royalty rate falls modestly if there are no valid patents.
Most past Halozyme drops this deep left buyers ahead a year later, after a further fall along the way. For buying now to work, royalties must keep growing. So far they are; royalty revenue is the number to watch at the next report, expected in February 2027. Halozyme’s patent fight is less settled, and the U.S. appeal could change that.
What Would Selling Halozyme Therapeutics Cost You In Tax?
If your shares have gained a lot, selling can bring a big tax bill, and holding keeps the risk. A free 30-minute strategy review with our partner advisory firm covers protecting the gain and a lower-tax way to trim.
Spot an error or want more like this? Tell us in 10 seconds.