NMRA
Arch Venture Partners X, Llc, NMRA's 10% owner, spent $5M of their own money on 1.92M shares at $3, growing their stake 46%.
+$5M
1.92M sh @ $3
ARCH Venture Partners X, LLC
10% Owner · SEC CIK 1769012Advertisement
Buy track record
How this insider's open-market purchases have performed0%
of buys now in profit
0 up · 9 down
Avg return since buy−65.4%
Median return−64.4%
Best trade−31.3%
Worst trade−89.6%
Buys scored9 (+2 n/a)
Average return by holding period — separates good entry timing from riding one long winner
After 1 month
+1.4%
33% won · 9 trades
After 3 months
−2.0%
56% won · 9 trades
After 6 months
−29.6%
11% won · 9 trades
After 12 months
−57.1%
14% won · 7 trades
| Date | Company | 90d trend | Buy price | Value | ΔOwn | 1M | 3M | 6M | 12M | To date |
|---|---|---|---|---|---|---|---|---|---|---|
| Oct 27, 2025 | NMRA | $3 | $5M | +46% | −16.7% | −20.8% | −17.5% | — | −33.8% | |
| Aug 1, 2025 | PRME | $3 | $10M | +95% | −22.8% | +12.9% | −5.9% | — | −31.3% | |
| Apr 2, 2024 | BOLD | $16 | $1.07M | +11% | −33.6% | −68.4% | −77.1% | −89.1% | −89.6% | |
| Apr 2, 2024 | BOLD | $16 | $2.13M | +13% | −33.6% | −68.4% | −77.1% | −89.1% | −89.6% | |
| Feb 15, 2024 | PRME | $6 | $20M | NEW | −8.2% | −13.3% | −43.7% | −61.7% | −64.4% | |
| Feb 8, 2024 | SANA | $6 | $2M | +3.5% | +54.2% | +54.1% | −24.4% | −55.6% | −56.5% | |
| Feb 8, 2024 | SANA | $6 | $4M | +6.2% | +54.2% | +54.1% | −24.4% | −55.6% | −56.5% | |
| Sep 19, 2023 | NMRA | $17 | $25.5M | +71% | −17.3% | +21.5% | +17.1% | +6.3% | −85.1% | |
| Oct 24, 2022 | PRME | $17 | $6.8M | +7.0% | +36.3% | +10.9% | −13.9% | −54.9% | −81.7% |
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 9 scored trades, treat this as a small sample, not a verdict.
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Open-market buys
$81.54M
11 trades
Open-market sells
$0
0 trades
Net flow
+$81.54M
Net buying
Total filings
18
transactions shown
Full transaction history
All Form 4 activity across every company, newest firstPRME
Arch Venture Partners X, Llc, PRME's 10% owner, spent $10M of their own money on 3.03M shares at $3, growing their stake 95%.
+$10M
3.03M sh @ $3
BOLD
+$0
1.05M sh
BOLD
Arch Venture Fund Ix, L.p., BOLD's 10% owner, spent $1.07M of their own money on 66,667 shares at $16, growing their stake 11%.
+$1.07M
66,667 sh @ $16
BOLD
Arch Venture Fund Ix, L.p., BOLD's 10% owner, spent $2.13M of their own money on 133,333 shares at $16, growing their stake 13%.
+$2.13M
133,333 sh @ $16
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PRME
Arch Venture Partners X, Llc, PRME's 10% owner, spent $20M of their own money on 3.2M shares at $6, opening a brand-new position.
+$20M
3.2M sh @ $6
SANA
Arch Venture Fund X, L.p., SANA's 10% owner, spent $2M of their own money on 363,637 shares at $6, growing their stake 4%.
+$2M
363,637 sh @ $6
SANA
Arch Venture Fund X, L.p., SANA's 10% owner, spent $4M of their own money on 727,272 shares at $6, growing their stake 6%.
+$4M
727,272 sh @ $6
NMRA
+$0
1.18M sh
NMRA
+$0
2.12M sh
NMRA
Arch Venture Partners X, Llc, NMRA's 10% owner, spent $25.5M of their own money on 1.5M shares at $17, growing their stake 71%.
+$25.5M
1.5M sh @ $17
PRME
+$0
5.73M sh
PRME
Arch Venture Partners X, Llc, PRME's 10% owner, spent $6.8M of their own money on 400,000 shares at $17, growing their stake 7%.
+$6.8M
400,000 sh @ $17
ERAS
+$0
5.53M sh
VERV
+$0
1.25M sh
SANA
+$0
11.72M sh
SNNA
Arch Venture Partners X, Llc, SNNA's 10% owner, spent $375K of their own money on 150,000 shares at $3, growing their stake 17%.
+$375K
150,000 sh @ $3
SNNA
Arch Venture Partners X, Llc, SNNA's 10% owner, spent $4.66M of their own money on 1.87M shares at $3, opening a brand-new position.
+$4.66M
1.87M sh @ $3
Frequently asked questions
How is ARCH Venture Partners X, LLC'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 ARCH Venture Partners X, LLC'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.