Palo Alto Investors LP
13F filer · CIK 1306923 · Palo Alto, CA
Summary
Palo Alto Investors LP reported $723.72M across 52 positions in its 13F for 2026 Q2, filed Aug 19, 2026. The largest holdings are PTCT (10.4%), ACAD (10.0%), INSM (6.1%). Versus 2026 Q1, leaving options aside, it opened 3 new positions, added to 5, trimmed 15 and sold out of 2.
Reported value$723.72M
Positions52
Report period2026 Q2
FiledAug 19, 2026
New positions3
Added5
Trimmed15
Sold out2
Top 25 holdings
By reported value, options listed separately · change vs 2026 Q1
Weight 10.4%Value $74.95MPrice $65.95Shares 919K -0.30%Since Jun 30 -19.15%
Weight 10.0%Value $72.46MPrice $20.22Shares 2.86M -0.30%Since Jun 30 -20.08%
Weight 6.1%Value $44.14MPrice $117.67Shares 414K -0.31%Since Jun 30 +10.36%
Weight 5.6%Value $40.83MPrice $87.96Shares 349K +7.27%Since Jun 30 -24.87%
Weight 5.6%Value $40.74MPrice $50.37Shares 603K -5.43%Since Jun 30 -25.38%
Weight 5.4%Value $39.07MPrice $59.87Shares 683K -0.35%Since Jun 30 +4.63%
Weight 5.1%Value $36.59MPrice $16.34Shares 1.65M -0.33%Since Jun 30 -26.43%
Weight 4.7%Value $33.91MPrice $485.54Shares 63K -0.35%Since Jun 30 -10.39%
Weight 4.2%Value $30.47MPrice $64.92Shares 417K +3.72%Since Jun 30 -11.24%
Weight 4.2%Value $30.31MPrice $227.07Shares 140K -0.31%Since Jun 30 +5.10%
Weight 3.0%Value $22.03MPrice $10.99Shares 5.30M -16.59%Since Jun 30 +164.18%
Weight 2.8%Value $19.92MPrice $14.41Shares 596KSince Jun 30 -56.84%
Weight 2.7%Value $19.40MPrice $15.83Shares 1.28MSince Jun 30 +4.49%
Weight 2.6%Value $18.91MPrice $17.86Shares 865KSince Jun 30 -18.30%
Weight 2.3%Value $16.83MPrice $4.13Shares 2.95MSince Jun 30 -27.67%
Weight 2.3%Value $16.34MPrice $18.56Shares 550KSince Jun 30 -37.49%
Weight 2.1%Value $15.16MPrice $64.02Shares 532KSince Jun 30 +124.63%
Weight 2.1%Value $14.88MPrice $31.64Shares 400K +34.90%Since Jun 30 -14.97%
Weight 1.8%Value $12.77MPrice $1.10Shares 5.83M +285.06%Since Jun 30 -49.77%
Weight 1.8%Value $12.71MPrice $40.80Shares 243KSince Jun 30 -22.13%
Weight 1.7%Value $12.14MPrice $36.65Shares 603KSince Jun 30 +82.13%
Weight 1.5%Value $11.19MPrice $8.72Shares 1.14M -5.41%Since Jun 30 -10.93%
Weight 1.3%Value $9.52MPrice $61.57Shares 168K -27.31%Since Jun 30 +8.38%
Weight 1.3%Value $9.48MPrice $4.99Shares 1.39MSince Jun 30 -26.73%
Weight 1.2%Value $8.54MPrice $5.28Shares 1.61MSince Jun 30 -0.19%
| Stock | Weight | Value | Since Jun 30 | Shares change | Action |
|---|---|---|---|---|---|
| 10.4% | $74.95M | -19.15% | -0.30% | Trim | |
| 10.0% | $72.46M | -20.08% | -0.30% | Trim | |
| 6.1% | $44.14M | +10.36% | -0.31% | Trim | |
| 5.6% | $40.83M | -24.87% | +7.27% | Add | |
| 5.6% | $40.74M | -25.38% | -5.43% | Trim | |
| 5.4% | $39.07M | +4.63% | -0.35% | Trim | |
| 5.1% | $36.59M | -26.43% | -0.33% | Trim | |
| 4.7% | $33.91M | -10.39% | -0.35% | Trim | |
| 4.2% | $30.47M | -11.24% | +3.72% | Add | |
| 4.2% | $30.31M | +5.10% | -0.31% | Trim | |
| 3.0% | $22.03M | +164.18% | -16.59% | Trim | |
| 2.8% | $19.92M | -56.84% | — | Hold | |
| 2.7% | $19.40M | +4.49% | — | Hold | |
| 2.6% | $18.91M | -18.30% | — | Hold | |
| 2.3% | $16.83M | -27.67% | — | Hold | |
| 2.3% | $16.34M | -37.49% | — | Hold | |
| 2.1% | $15.16M | +124.63% | — | Hold | |
| 2.1% | $14.88M | -14.97% | +34.90% | Add | |
| 1.8% | $12.77M | -49.77% | +285.06% | Add | |
| 1.8% | $12.71M | -22.13% | — | Hold | |
| 1.7% | $12.14M | +82.13% | — | New | |
| 1.5% | $11.19M | -10.93% | -5.41% | Trim | |
| 1.3% | $9.52M | +8.38% | -27.31% | Trim | |
| 1.3% | $9.48M | -26.73% | — | Hold | |
| 1.2% | $8.54M | -0.19% | — | Hold |
Weight is the share of the reported 13F value, including options at notional value. “Since Jun 30” compares the latest close with the quarter-end price implied by the filing (value ÷ shares).
Largest buys in 2026 Q2
Largest sells in 2026 Q2
Source: SEC Form 13F, values as reported by the filer. Filings lag up to 45 days after quarter end and cover only certain long positions. Research only, not investment advice.