PHAT
+$0
24,122 sh
Topper James N
Director, 10% Owner, Chief Executive Officer · SEC CIK 1341382
Insider at
PHAT Phathom Pharmaceuticals, Inc.
MBX MBX Biosciences, Inc.
NAMS NewAmsterdam Pharma Co N.V.
HLVX HilleVax, Inc.
ALPN ALPINE IMMUNE SCIENCES, INC.
ARQT Arcutis Biotherapeutics, Inc.
ANAB ANAPTYSBIO, INC
FLAC Frazier Lifesciences Acquisition Corp
ALNA Allena Pharmaceuticals, Inc.
TARS Tarsus Pharmaceuticals, Inc.
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Buy track record
How this insider's open-market purchases have performed95%
of buys now in profit
19 up · 1 down
Avg return since buy+146.5%
Median return+65.5%
Best trade+920.1%
Worst trade−3.1%
Buys scored20 (+4 n/a)
Average return by holding period — separates good entry timing from riding one long winner
After 1 month
+64.0%
70% won · 20 trades
After 3 months
+87.5%
75% won · 20 trades
After 6 months
+132.2%
85% won · 20 trades
After 12 months
+146.6%
77% won · 13 trades
| Date | Company | 90d trend | Buy price | Value | ΔOwn | 1M | 3M | 6M | 12M | To date |
|---|---|---|---|---|---|---|---|---|---|---|
| Sep 26, 2025 | MBX | $18 | $12M | +15% | −0.4% | +76.5% | +61.6% | — | +102.8% | |
| Sep 15, 2025 | NAMS | $24 | $15.6K | — | +67.7% | +46.6% | +23.5% | — | +26.0% | |
| Sep 8, 2025 | NAMS | $25 | $31.5K | — | +31.0% | +42.5% | +22.6% | — | +21.2% | |
| Aug 11, 2025 | NAMS | $24 | $11.3K | — | +9.2% | +63.7% | +40.5% | — | +24.7% | |
| Jun 25, 2025 | NAMS | $18 | $23K | — | +28.8% | +43.4% | +92.4% | — | +65.8% | |
| Jun 24, 2025 | NAMS | $18 | $46.5K | +0.1% | +27.1% | +45.4% | +93.8% | — | +65.2% | |
| Jun 16, 2025 | NAMS | $19 | $167.4K | +0.3% | +5.9% | +24.2% | +73.3% | — | +53.9% | |
| May 21, 2025 | PHAT | $4 | $14.6K | +6.8% | +142.8% | +180.8% | +284.6% | +196.9% | +165.9% | |
| May 14, 2025 | PHAT | $3 | $20.9K | +13% | +227.4% | +222.2% | +348.0% | +301.5% | +219.1% | |
| May 13, 2025 | PHAT | $3 | $3.5K | +2.3% | +221.5% | +216.6% | +348.6% | +279.5% | +213.3% | |
| May 12, 2025 | PHAT | $3 | $38.3K | +35% | +218.4% | +229.5% | +364.1% | +297.8% | +229.2% | |
| May 9, 2025 | PHAT | $3 | $106.6K | NEW | +181.2% | +227.4% | +337.3% | +289.2% | +230.3% | |
| May 9, 2025 | PHAT | $4 | $8.1K | +6.7% | +181.2% | +227.4% | +337.3% | +289.2% | +230.3% | |
| Mar 26, 2025 | NAMS | $22 | $25.5K | — | −21.0% | −18.2% | +26.3% | +38.5% | +34.8% | |
| Mar 4, 2025 | NAMS | $21 | $84.2K | +0.1% | −26.5% | −9.8% | +19.3% | +45.0% | +41.4% | |
| Sep 16, 2024 | MBX | $16 | $10M | +16% | +11.7% | −11.6% | −59.1% | −55.0% | +64.0% | |
| Mar 26, 2024 | NAMS | $22 | $181.2K | +0.3% | −3.2% | −13.1% | −30.3% | −0.7% | +33.8% | |
| Oct 24, 2023 | ARQT | $3 | $200K | +0.9% | −15.1% | +90.8% | +266.1% | +251.9% | +920.1% | |
| Aug 5, 2022 | ARQT | $20 | $5M | +3.0% | −16.2% | −26.4% | −34.3% | −61.9% | −3.1% | |
| Oct 20, 2020 | TARS | $16 | $5M | +19% | +8.4% | +92.9% | +28.1% | +34.0% | +192.1% |
How this is calculated. We score only open-market purchases (SEC code
P) — the buys that carry real signal. Each trade's return is measured from the adjusted closing price on the purchase date to the latest close, accounting for stock splits and dividends. The 1M/3M/6M/12M columns show the same trade's return after each fixed holding period; a dash means that horizon hasn't elapsed yet or isn't priceable. Sales are excluded because insiders sell for many routine reasons. With only 20 scored trades, treat this as a small sample, not a verdict.
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Open-market buys
$73.91M
24 trades
Open-market sells
$1.2K
1 trades
Net flow
+$73.91M
Net buying
Total filings
41
transactions shown
Full transaction history
All Form 4 activity across every company, newest firstMBX
Heron Patrick J, MBX's 10% owner, spent $12M of their own money on 666,666 shares at $18, growing their stake 15%.
+$12M
666,666 sh @ $18
HLVX
−$16.64M
8.54M sh @ $2
HLVX
−$33.5K
17,199 sh @ $2
NAMS
Topper James N, NAMS's Director, spent $15.6K of their own money on 660 shares at $24.
+$15.6K
660 sh @ $24
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NAMS
Topper James N, NAMS's Director, spent $31.5K of their own money on 1,260 shares at $25.
+$31.5K
1,260 sh @ $25
NAMS
Topper James N, NAMS's Director, spent $11.3K of their own money on 471 shares at $24.
+$11.3K
471 sh @ $24
NAMS
Topper James N, NAMS's Director, spent $23K of their own money on 1,260 shares at $18.
+$23K
1,260 sh @ $18
NAMS
Topper James N, NAMS's Director, spent $46.5K of their own money on 2,520 shares at $18.
+$46.5K
2,520 sh @ $18
NAMS
Topper James N, NAMS's Director, spent $167.4K of their own money on 8,584 shares at $19.
+$167.4K
8,584 sh @ $19
PHAT
+$0
10,500 sh
PHAT
Topper James N, PHAT's Director, spent $14.6K of their own money on 3,780 shares at $4, growing their stake 7%.
+$14.6K
3,780 sh @ $4
PHAT
Topper James N, PHAT's Director, spent $20.9K of their own money on 6,300 shares at $3, growing their stake 13%.
+$20.9K
6,300 sh @ $3
PHAT
Topper James N, PHAT's Director, spent $3.5K of their own money on 1,120 shares at $3, growing their stake 2%.
+$3.5K
1,120 sh @ $3
PHAT
Topper James N, PHAT's Director, spent $38.3K of their own money on 12,601 shares at $3, growing their stake 35%.
+$38.3K
12,601 sh @ $3
PHAT
Topper James N, PHAT's Director, spent $106.6K of their own money on 33,376 shares at $3, opening a brand-new position.
+$106.6K
33,376 sh @ $3
PHAT
Topper James N, PHAT's Director, spent $8.1K of their own money on 2,226 shares at $4, growing their stake 7%.
+$8.1K
2,226 sh @ $4
NAMS
Topper James N, NAMS's Director, spent $25.5K of their own money on 1,135 shares at $22.
+$25.5K
1,135 sh @ $22
NAMS
Topper James N, NAMS's Director, spent $84.2K of their own money on 4,005 shares at $21.
+$84.2K
4,005 sh @ $21
MBX
+$0
3.93M sh
MBX
Frazier Life Sciences X, L.p., MBX's 10% owner, spent $10M of their own money on 625,000 shares at $16, growing their stake 16%.
+$10M
625,000 sh @ $16
PHAT
+$0
10,500 sh
ALPN
−$0
2.83M sh
ALPN
+$1.2K
1.2M sh @ $0
ALPN
−$1.2K
19 sh @ $65
HLVX
Frazier Life Sciences X, L.p., HLVX's 10% owner, spent $128.3K of their own money on 8,850 shares at $15.
+$128.3K
8,850 sh @ $15
NAMS
Topper James N, NAMS's Director, spent $181.2K of their own money on 8,429 shares at $22.
+$181.2K
8,429 sh @ $22
ALPN
+$1.85M
145,251 sh @ $13
ARQT
Frazier Life Sciences Viii, L.p., ARQT's 10% owner, spent $200K of their own money on 80,000 shares at $3, growing their stake 1%.
+$200K
80,000 sh @ $3
PHAT
+$0
9,000 sh
Frequently asked questions
How is Topper James N's win rate calculated?
We take every open-market purchase (SEC code P) we can match to a stock price, then compare the split- and dividend-adjusted price on the purchase date to the most recent close. The win rate is the share of those buys currently trading above the purchase price. Sales and share grants are not scored.
Why are some buys not included in the score?
A purchase is excluded if we can't price it — for example if the ticker is missing from the filing, the company has been delisted, or the security isn't a common stock we can match to market data. Excluded counts are shown next to the scored total.
What do the 1M / 3M / 6M / 12M columns mean?
They show each purchase's return after a fixed holding period — one, three, six, and twelve months from the buy date — using split- and dividend-adjusted prices. This separates good entry timing from simply holding a long-running winner. A dash means that horizon hasn't elapsed yet for that trade, or the stock couldn't be priced at that date.
Does a high win rate mean I should copy this insider?
No. Past performance does not predict future results, sample sizes are often small, and an insider's edge in their own company doesn't transfer to yours. This is context, not a recommendation. InsiderSource is not investment advice.
Where does this data come from?
Trades come from Topper James N's SEC Form 4 filings on EDGAR. Prices come from public market data and are split/dividend-adjusted. Always verify against the original filings before acting.