PRTAProthena Corporation plcHealthcare · Biotechnologyas of 2026-09-16
Horizon

Issued 2026-09-16 at $8.24 · now $8.24 (2026-09-16, +0.0% since)

Based on its own history, a month from the 2026-09-16 close, PRTA has typically landed between $6.15 and $10.07 — a range of −25.4% to +22.2% from the issuance price $8.24.

Range of outcomes in historically similar periods — not a price prediction. Ranges are scored publicly on /methodology.
  • Actual close
  • Typical path (median)
  • Middle 50% of outcomes
  • 90% range

3,430 overlapping 1 month windows · 2012-12-21 – 2026-08-17 · basis climatology · forecast (batch). Probability up 53.9% (90% CI 51.7–56.1%, ≈1,408 obs).

The cone is anchored at the 2026-09-16 issuance close ($8.24) — the price the forecast resolves against on 2026-10-15, not the latest close. The drawn path shape is illustrative (bands widen with √t); every labeled number is real — the anchor, the scored batch p90/IQR endpoints, and the typical move.

Where PRTA has typically landed a month from the 2026-09-16 close of $8.24 — the range is history, not a prediction.

$6.15worst · -25.4%$10.07best · +22.2%
  • now $8.24 (+0.0%)
  • typicalThe typical outcome — half of similar past periods did better and half did worse (not an average, so a few wild periods don't skew it). $7.91 (-4.0%)
  • middle 50%The central range of outcomes — half of similar past periods landed inside it, a quarter finished above, a quarter below. $7.13–$8.69
  • 90% rangeA nine-in-ten range — in about nine of every ten similar past periods the outcome stayed within these bounds. $6.15–$10.07
Actual 1-month windows behind the coneiEvery overlapping 1-month window in this security's own price history was ranked by realized return; shown are the 3 worst and 3 best of 3,430 windows spanning 2012-12-21 to 2026-09-16. Not cherry-picked — these are the extremes of the full sample. Max drop / max rise are the deepest and highest points reached within each window. See /methodology.
StartReturnMax dropMax rise
3 worst
2018-03-23−71.2%−71.2%+15.7%
2018-03-22−71.0%−71.0%+15.7%
2018-03-26−70.0%−72.1%+12.4%
3 best
2021-05-17+150.7%+0.0%+150.7%
2022-09-06+132.8%+0.0%+145.7%
2021-05-14+126.2%+0.0%+126.2%

3,430 overlapping windows · 2012-12-21 – 2026-09-16 · not cherry-picked

Seasonality · by month iHow this security has tended to do in each calendar month historically — a frequency, never a prediction.

iFor each calendar month, the share of years this security closed higher than the month before, and the average month-over-month return, over ~14 years of its own price history. Cells are shaded by average return. This is historical frequency, not a prediction — no month is a signal.
Jan
36%
−7.4%
n=14
Feb
57%
+9.0%
n=14
Mar
64%
+4.9%
n=14
Apr
43%
−10.3%
n=14
May
50%
+1.0%
n=14
Jun
64%
+12.6%
n=14
Jul
71%
+9.8%
n=14
Aug
50%
+3.8%
n=14
Sep
43%
+4.1%
n=14
Oct
54%
−1.0%
n=13
Nov
54%
+6.7%
n=13
Dec
23%
−4.9%
n=13

Up-frequency and average month-over-month return · historical frequency, not a prediction

Reported insider & political trades

Every Form 4 the people closest to this company have filed with the SEC — plotted against the share price, aggregated by month, and shown with the gap between when each trade happened and when it was disclosed. A public record, not advice.

Share price & reported tradesMonthly open-market valueReporting lag — trade date to filing date2026-092026-082026-072026-062026-052026-042026-032026-022026-012025-122025-112025-102025-092025-08$12$82026-09-02: 1 insider purchase, $256K — SCULLY WILLIAM P2026-08-20: 1 insider purchase, $439K — SCULLY WILLIAM P2026-08-07: 2 insider purchases, $323K — SCULLY WILLIAM P …2026-07-29: 2 insider sales, $136K — Isaacs Michael John, Kingston Anne Evans2026-06-16: 1 insider purchase, $158K — SCULLY WILLIAM P2026-06-11: 1 insider purchase, $1.0M — SCULLY WILLIAM P2026-06-04: 1 insider purchase, $465K — SCULLY WILLIAM P2026-06-02: 1 insider purchase, $471K — SCULLY WILLIAM P2026-05-22: 1 insider purchase, $981K — SCULLY WILLIAM P2026-05: 1 open-market purchase, $981K2026-06: 4 open-market purchases, $2.1M2026-07: 2 open-market sales, $136K2026-08: 3 open-market purchases, $763K2026-09: 1 open-market purchase, $256K↑ buys↓ salestenPercentOwner SCULLY WILLIAM P — Purchase on 2026-09-02, filed 1 day after the tradetenPercentOwner SCULLY WILLIAM P — Purchase on 2026-08-20, filed 1 day after the tradetenPercentOwner SCULLY WILLIAM P — Purchase on 2026-08-07, filed 3 days after the tradetenPercentOwner SCULLY WILLIAM P — Purchase on 2026-08-07, filed 3 days after the tradeofficer Isaacs Michael John — Sale on 2026-07-29, filed 1 day after the tradeofficer Kingston Anne Evans — Sale on 2026-07-29, filed 1 day after the tradetenPercentOwner SCULLY WILLIAM P — Purchase on 2026-06-16, filed 2 days after the tradetenPercentOwner SCULLY WILLIAM P — Purchase on 2026-06-11, filed 1 day after the tradetenPercentOwner SCULLY WILLIAM P — Purchase on 2026-06-04, filed 1 day after the tradetenPercentOwner SCULLY WILLIAM P — Purchase on 2026-06-02, filed 1 day after the tradetenPercentOwner SCULLY WILLIAM P — Purchase on 2026-05-22, filed 4 days after the trade
DatePersonRoleActionShares @ priceValueOwnership Δvs S&P 1mvs S&P 6mOwned afterFiling
2026-09-02SCULLY WILLIAM PtenPercentOwnerPurchase27,000 @ $9.47$256K+3.4% of holdingnot yet — horizon still opennot yet — horizon still open827,000Form 4 · filed 1 day after the trade
2026-08-20SCULLY WILLIAM PtenPercentOwnerPurchase50,000 @ $8.79$439K+6.7% of holdingnot yet — horizon still opennot yet — horizon still open800,000Form 4 · filed 1 day after the trade
2026-08-07SCULLY WILLIAM PtenPercentOwnerPurchase34,000 @ $8.62$293K+4.5% of holding+9.8%not yet — horizon still open790,000Form 4 · filed 3 days after the trade
2026-08-07SCULLY WILLIAM PtenPercentOwnerPurchase3,500 @ $8.62$30K+4.4% of holding+9.8%not yet — horizon still open83,500Form 4 · filed 3 days after the trade
2026-07-29Isaacs Michael JohnofficerSale8,386 @ $8.47$71K−19.0% of holding+0.5%not yet — horizon still open35,745Form 4 · filed 1 day after the trade
2026-07-29Kingston Anne EvansofficerSale7,662 @ $8.47$65K−12.1% of holding+0.5%not yet — horizon still open55,782Form 4 · filed 1 day after the trade
2026-06-16SCULLY WILLIAM PtenPercentOwnerPurchase20,000 @ $7.90$158K+2.7% of holding+5.1%not yet — horizon still open756,000Form 4 · filed 2 days after the trade
2026-06-11SCULLY WILLIAM PtenPercentOwnerPurchase125,000 @ $8.17$1.0M+13.4% of holding+2.4%not yet — horizon still open1,061,000Form 4 · filed 1 day after the trade
2026-06-04SCULLY WILLIAM PtenPercentOwnerPurchase50,000 @ $9.31$465K+5.6% of holding+5.6%not yet — horizon still open936,000Form 4 · filed 1 day after the trade
2026-06-02SCULLY WILLIAM PtenPercentOwnerPurchase50,000 @ $9.43$471K+6.0% of holding+7.1%not yet — horizon still open886,000Form 4 · filed 1 day after the trade
2026-05-22SCULLY WILLIAM PtenPercentOwnerPurchase100,000 @ $9.81$981K+13.6% of holding−3.0%not yet — horizon still open836,000Form 4 · filed 4 days after the trade
2025-05-06EcoR1 Capital, LLCdirectorSale1,984,053 @ $7.64$15.2M−27.2% of holding−37.3%+18.1%5,304,596Form 4 · filed same day
2025-05-05EcoR1 Capital, LLCdirectorSale977,693 @ $8.11$7.9M−11.8% of holding−45.4%+8.5%7,288,649Form 4 · filed 1 day after the trade
2025-05-02EcoR1 Capital, LLCdirectorSale3,317,938 @ $8.36$27.7M−28.6% of holding−48.4%+5.4%8,266,342Form 4 · filed 4 days after the trade
2025-01-14SCULLY WILLIAM PtenPercentOwnerPurchase100,000 @ $12.79$1.3M+15.7% of holding+4.9%−57.5%735,993Form 4 · filed 108 days after the trade
2024-12-31SCULLY WILLIAM PtenPercentOwnerPurchase30,000 @ $12.99$390K+4.8% of holding−5.0%−61.1%650,193Form 4 · filed 122 days after the trade
2024-12-31SCULLY WILLIAM PtenPercentOwnerPurchase1,200 @ $13.37$16K+0.2% of holding−5.0%−61.1%619,393Form 4 · filed 122 days after the trade
2024-12-31SCULLY WILLIAM PtenPercentOwnerPurchase800 @ $13.39$11K+0.1% of holding−5.0%−61.1%620,193Form 4 · filed 122 days after the trade
2024-12-20SCULLY WILLIAM PtenPercentOwnerPurchase2,000 @ $15.91$32K+0.3% of holding−0.2%−63.5%618,693Form 4 · filed 133 days after the trade
2024-12-18SCULLY WILLIAM PtenPercentOwnerPurchase73,436 @ $13.93$1.0M+6.0% of holding+17.0%−53.7%1,297,693Form 4 · filed 135 days after the trade

The vs-S&P columns are a labeled look-back on what the stock did after each filing, measured against the index over the same window. Descriptive history, not a claim about the person or a reason to trade.

77 award / exercise / gift records — not counted as purchases

Awards, option exercises, gifts and tax-withholding disposals are shown separately and never counted as open-market purchases or sales — they carry no conviction information.

DatePersonRoleActionSharesOwned afterFiling
2026-08-18SCULLY WILLIAM PtenPercentOwnerGift627,553750,000Form 4
2026-08-17SCULLY WILLIAM PtenPercentOwnerGift336,0001,377,553Form 4
2026-08-10SCULLY WILLIAM PtenPercentOwnerGift251,5531,041,553Form 4
2026-07-28Kinney Gene G.directorDisposition84,00068,793Form 4
2026-07-28Smith Brandon S.officerDisposition78,00052,000Form 4
2026-07-28Nguyen TranofficerDisposition57,00040,205Form 4
2026-07-28Zago Wagner M.officerDisposition51,00034,000Form 4
2026-07-28Swanson Chad J.officerDisposition40,80044,200Form 4
2026-07-28Walker Karin LofficerDisposition15,00010,000Form 4
2026-07-28Isaacs Michael JohnofficerWithheld for tax4,69444,131Form 4
2026-07-28Kingston Anne EvansofficerWithheld for tax3,49863,444Form 4
2026-07-28Swanson Chad J.officerWithheld for tax3,46740,733Form 4
2026-07-28Kinney Gene G.directorOption exercise84,0000Form 4
2026-07-28Smith Brandon S.officerOption exercise78,0000Form 4
2026-07-28Nguyen TranofficerOption exercise57,0000Form 4
2026-07-28Walker Karin LofficerOption exercise15,0000Form 4
2026-07-28Swanson Chad J.officerOption exercise51,0000Form 4
2026-07-28Zago Wagner M.officerOption exercise51,0000Form 4
2026-07-28Smith Brandon S.officerOption exercise78,000130,000Form 4
2026-07-28Kinney Gene G.directorOption exercise84,000152,793Form 4
2026-07-28Nguyen TranofficerOption exercise57,00097,205Form 4
2026-07-28Kinney Gene G.directorOption exercise84,000152,793Form 4
2026-07-28Nguyen TranofficerOption exercise57,00097,205Form 4
2026-07-28Smith Brandon S.officerOption exercise78,000130,000Form 4
2026-07-28Swanson Chad J.officerOption exercise51,00085,000Form 4
2026-07-28Walker Karin LofficerOption exercise15,00025,000Form 4
2026-07-28Zago Wagner M.officerOption exercise51,00085,000Form 4
2026-07-28Swanson Chad J.officerOption exercise51,00085,000Form 4
2026-07-28Walker Karin LofficerOption exercise15,00025,000Form 4
2026-07-28Zago Wagner M.officerOption exercise51,00085,000Form 4
2026-06-15SCULLY WILLIAM PtenPercentOwnerGift325,000736,000Form 4
2026-05-15WELCH DANIEL GdirectorAward / grant27,00027,000Form 4
2026-05-15Dunn William H. Jr.directorAward / grant27,00027,000Form 4
2026-05-15Selkoe Dennis J.directorAward / grant27,00027,000Form 4
2026-05-15Cooke ShanedirectorAward / grant27,00027,000Form 4
2026-05-15Ekman LarsdirectorAward / grant27,00027,000Form 4
2026-05-15COLLIER RICHARD TdirectorAward / grant27,00027,000Form 4
2026-04-10Kingston Anne EvansofficerAward / grant100,000100,000Form 4
2026-03-03Swanson Chad J.officerAward / grant190,000190,000Form 4
2026-03-03Nguyen TranofficerAward / grant230,000230,000Form 4

Source: SEC Form 4 filings. Each row links to its original filing.

Across 2012–2021, stocks where a CEO, C-suite officer, or director had recently made an open-market common-stock purchase ran about +28 bp per month above the universe average (n=34,268 stock-weeks). A historical tendency, not a prediction.

Congressional disclosures

No congressional trades disclosed for this company.

Research tool, not investment advice — historical frequencies, not recommendations. A product of Marovel Technologies LLC. Full terms.