undamentalytics Newsletter

Marcus Joel S: insider trades

Chief executive, Officer, Director at 4 companies we cover. 8 open-market purchases and 102 sales not made under a pre-set plan, reported from March 9, 2010 to September 15, 2026.

Would copying Marcus Joel S’s purchases have beaten the S&P 500?

Too few purchases to judge. Only 2 purchases have 12 months of prices after the report; we judge insiders once they have 20. The figures below can swing a long way on a handful of trades. Buying each purchase the day after it was reported, an equal amount each, and holding it 12 months or until they reported a sale would have turned $10,000 on March 12, 2015 into $7,709 by November 2, 2026, −2.2% a year. The copy held shares only 18% of the time, so the fair comparison is the S&P 500 on those same days with Treasury bills otherwise: $16,056, +4.2% a year (the S&P 500 held throughout made $44,331, +13.7% a year). Beta against the index was 0.17. Twelve months after each report, the average purchase was −77.5% against the S&P 500 (median −77.5%), and 0% beat it. Measured from the trade date, the insider’s own timing, the average was −69.5%. After their sales, the shares moved −10.4% against the index over 12 months on average (a negative figure means selling was the right call); 65% trailed it.

With 296 insiders tested, some will look skilled or unskilled by chance alone: when we replaced each insider’s stocks with random companies bought on the same days, about 5.7 cleared the bar ahead and 23.3 behind. One record on its own proves little.

$0$20.0k$40.0k 201520172019202120232025 $44.3k$16.1k$7.7k
Copying Marcus Joel SS&P 500, same days investedS&P 500, held throughout $10,000 copying Marcus Joel S’s open-market purchases from March 12, 2015, before costs and taxes, marked weekly. Each purchase gets the same starting stake, bought at the close of the first trading day after the report and sold 12 months later or the day after a reported sale of that stock; uninvested money earns the Treasury bill rate. “Same days invested” holds the S&P 500 only on the days the copy held shares, Treasury bills otherwise.
Return a year, copying
−2.2%
S&P 500, same days invested
+4.2% (held throughout +13.7%)
Time in shares
18%
Sharpe ratio (S&P 500)
0.05 (0.69)
Biggest drop (S&P 500)
−78% (−34%)
Market sensitivity (beta)
0.17
Purchases copied
8

Trade by trade

Marcus Joel S: trades against the S&P 500 afterwards
MeasuredTrades countedAverage vs S&P 500MedianWent the right wayYearst-statisticp-valueEvidence
Purchases, 3 months after the report 6 +0.5% +1.5% 67% 3 — — Not enough years
Purchases, 6 months after the report 3 +23.4% +45.9% 67% 3 — — Not enough years
Purchases, 12 months after the report 2 −77.5% −77.5% 0% 2 — — Not enough years
Purchases, 12 months after the trade 2 −69.5% −69.5% 0% 2 — — Not enough years
Sales, 3 months after the report 102 −3.0% −1.8% 59% 15 −2.17 0.048 Some evidence: seller right
Sales, 12 months after the report 102 −10.4% −8.4% 65% 15 −2.81 0.014 Some evidence: seller right
Sales, 12 months after the trade 102 −10.2% −6.3% 62% 15 −2.72 0.017 Some evidence: seller right

“Average vs S&P 500” is the stock’s return including dividends minus the index’s over the same dates, from the close on the first trading day after the report, or from the close on the trade date. Only windows that have finished are counted. For sales, a negative figure means the stock lagged after it was sold, so selling was the right call (green). “Went the right way” is the share of purchases that beat the index, or of sales that trailed it. The t-statistic uses one average per year of reports, because one person’s trades bunch into the same stock and weeks, and needs trades in at least four different years; the p-value comes from the t distribution with that number of years (with four years, a t of 2 has p = 0.14). “Some evidence” means p under 5%, “strong evidence” p under 1% over at least six years.

Companies traded

CompanyTitle on the latest filingPurchasesSalesFirst reportLatest report
Alexandria Real Estate Equities ARE Executive Chairman694March 9, 2010September 15, 2026
Atara Biotherapeutics, Inc. ATRA —13March 11, 2015March 19, 2019
Korro Bio, Inc. KRRO —13May 20, 2020December 22, 2020
Meiragtx Holdings plc MGTX —02May 14, 2020August 12, 2020

Trades and what followed

Moves are against the S&P 500; green means the trade went the insider’s way.

ReportedTradedCompanyTradeValue3 months after report12 months after report12 months after trade
September 15, 2026September 11, 2026 ARE Purchase $248,400 not yetnot yetnot yet
August 19, 2026August 17, 2026 ARE Purchase $231,400 not yetnot yetnot yet
May 7, 2026May 6, 2026 ARE Purchase $347,558 +0.8%not yetnot yet
May 6, 2026May 5, 2026 ARE Purchase $320,416 +4.6%not yetnot yet
May 5, 2026May 4, 2026 ARE Purchase $410,200 +2.2%not yetnot yet
February 13, 2026February 12, 2026 ARE Purchase $1,347,889 −21.3%not yetnot yet
February 28, 2024February 26, 2024 ARE Sale $891,900 −9.0%−30.6%−28.4%
May 10, 2023May 8, 2023 ARE Sale $916,500 −6.0%−23.5%−26.3%
February 9, 2023February 7, 2023 ARE Sale $1,512,000 −28.4%−51.8%−48.0%
December 14, 2022December 12, 2022 ARE Sale $975,000 −20.2%−34.0%−32.5%
December 7, 2022December 5, 2022 ARE Sale $380,000 −12.1%−34.6%−31.2%
August 11, 2021August 9, 2021 ARE Sale $1,557,075 −3.5%−12.1%−14.9%
August 4, 2021August 2, 2021 ARE Sale $1,013,150 −4.8%−15.8%−13.9%
July 30, 2021July 28, 2021 ARE Sale $4,000,100 −4.1%−13.9%−9.8%
May 5, 2021May 3, 2021 ARE Sale $3,607,000 +12.3%+3.8%+0.9%
December 22, 2020December 18, 2020 KRRO Sale $1,702,370 −81.6%−113.2%−108.0%
August 19, 2020August 17, 2020 ARE Sale $1,293,365 −10.3%−9.1%−11.2%
August 12, 2020August 11, 2020 MGTX Sale $216,570 +4.1%−35.7%−35.3%
August 4, 2020July 31, 2020 ARE Sale $7,898,000 −11.8%−13.3%−18.7%
July 22, 2020July 20, 2020 KRRO Purchase $999,990 −14.1%−105.2%−97.3%
June 9, 2020June 5, 2020 ARE Sale $3,911,950 −3.2%−9.0%−13.0%
May 22, 2020May 21, 2020 KRRO Sale $94,050 +1.0%−95.3%−99.1%
May 20, 2020May 18, 2020 KRRO Sale $524,736 +4.2%−99.1%−96.5%
May 14, 2020May 12, 2020 MGTX Sale $77,621 −14.4%−50.1%−58.3%
May 7, 2020May 5, 2020 ARE Sale $3,821,550 +1.4%−24.3%−29.8%
May 4, 2020April 30, 2020 ARE Sale $1,568,200 +0.3%−29.8%−27.7%
February 14, 2020February 12, 2020 ARE Sale $6,055,000 −3.9%−18.6%−16.1%
October 1, 2019September 27, 2019 ARE Sale $1,158,675 −7.5%−8.9%−7.8%
September 10, 2019September 6, 2019 ARE Sale $1,489,312 +2.2%−5.3%−5.6%
August 12, 2019August 8, 2019 ARE Sale $3,648,250 +2.3%+5.7%+7.0%
August 5, 2019August 1, 2019 ARE Sale $2,902,000 +2.4%+6.6%+12.3%
May 10, 2019May 8, 2019 ARE Sale $1,195,695 −2.2%+2.6%+9.3%
May 6, 2019May 2, 2019 ARE Sale $2,130,450 +3.7%+10.6%+11.0%
March 29, 2019March 27, 2019 ARE Sale $6,408,050 −2.0%+7.5%+6.6%
March 19, 2019March 15, 2019 ATRA Sale $765,000 −47.9%−66.1%−70.5%
March 1, 2019February 28, 2019 ATRA Sale $2,257,621 −38.8%−77.5%−74.4%
February 20, 2019February 15, 2019 ARE Sale $1,344,100 +4.8%+4.9%+8.7%
February 11, 2019February 7, 2019 ARE Sale $1,300,100 +5.4%+9.0%+4.4%
December 13, 2018December 11, 2018 ARE Sale $1,262,600 +5.5%+6.3%+10.0%
December 4, 2018November 30, 2018 ARE Sale $1,246,250 +6.8%+12.2%+18.8%
November 8, 2018November 7, 2018 ATRA Sale $363,500 +8.7%−77.6%−75.8%
November 8, 2018November 6, 2018 ARE Sale $614,050 +9.4%+14.5%+14.3%
November 5, 2018November 1, 2018 ARE Sale $1,230,200 +9.4%+14.3%+17.7%
August 22, 2018August 20, 2018 ARE Sale $1,283,800 +4.0%+17.2%+14.8%
August 6, 2018August 2, 2018 ARE Sale $3,742,665 +0.7%+13.6%+14.2%
May 14, 2018May 10, 2018 ARE Sale $1,690,000 −4.2%+13.4%+8.5%
May 9, 2018May 7, 2018 ARE Sale $2,570,600 −6.8%+8.5%+1.2%
May 7, 2018May 3, 2018 ARE Sale $3,187,290 −7.4%+3.6%+1.7%
February 20, 2018February 15, 2018 ARE Sale $604,300 +4.0%+13.8%+11.3%
February 5, 2018February 1, 2018 ARE Sale $3,760,992 +9.5%+13.2%+9.4%
December 6, 2017December 4, 2017 ARE Sale $3,564,000 −7.0%−0.8%−5.6%
December 4, 2017November 30, 2017 ARE Sale $1,649,830 −4.3%−0.5%−5.0%
September 27, 2017September 25, 2017 ARE Sale $2,974,750 +4.5%−8.0%−12.1%
August 17, 2017August 15, 2017 ARE Sale $1,877,980 −1.2%−9.7%−9.0%
August 7, 2017August 3, 2017 ARE Sale $1,684,053 −0.3%−9.3%−8.3%
May 12, 2017May 10, 2017 ARE Sale $573,850 +2.7%−4.7%+0.7%
May 8, 2017May 4, 2017 ARE Sale $1,580,880 +3.2%+3.0%+2.2%
March 21, 2017March 17, 2017 ARE Sale $1,048,515 +3.5%−1.8%+2.5%
February 8, 2017February 6, 2017 ARE Sale $731,900 −3.4%−9.9%−11.6%
February 3, 2017February 2, 2017 ARE Sale $1,410,760 −2.6%−11.6%−6.1%
November 7, 2016November 3, 2016 ARE Sale $3,107,400 −0.1%−2.0%−0.4%
May 9, 2016May 5, 2016 ARE Sale $2,378,900 +13.1%+5.5%+4.4%
March 3, 2016March 1, 2016 ARE Sale $402,250 +12.3%+23.8%+26.4%
December 21, 2015December 17, 2015 ARE Sale $363,640 −2.2%+10.5%+9.9%
December 15, 2015December 11, 2015 ARE Sale $355,200 −1.4%+9.0%+13.2%
December 8, 2015December 4, 2015 ARE Sale $453,400 −2.8%+16.1%+17.6%
August 11, 2015August 7, 2015 ARE Sale $922,850 −3.2%+17.3%+18.2%
June 15, 2015June 11, 2015 ARE Sale $1,368,850 +1.4%+10.1%+9.7%
March 20, 2015March 18, 2015 ARE Sale $1,212,257 −9.9%−9.6%−6.3%
March 11, 2015March 9, 2015 ATRA Purchase $118,285 +30.7%−49.9%−41.6%
March 9, 2015March 5, 2015 ARE Sale $19,600 −5.9%−7.4%−8.8%
February 9, 2015February 5, 2015 ARE Sale $1,441,100 −3.5%−11.9%−11.4%
December 11, 2014December 9, 2014 ARE Sale $364,760 +7.9%+1.3%+0.8%
November 12, 2014November 10, 2014 ARE Sale $749,790 +11.2%+7.4%+5.3%
August 18, 2014August 14, 2014 ARE Sale $156,760 +1.5%+15.6%+14.7%
August 5, 2014August 1, 2014 ARE Sale $589,275 +3.4%+12.4%+13.7%
May 13, 2014May 9, 2014 ARE Sale $562,800 +1.9%+14.0%+12.2%
February 20, 2014February 18, 2014 ARE Sale $361,600 −0.2%+21.6%+21.5%
September 20, 2013September 18, 2013 ARE Sale $326,650 −9.5%−3.4%−1.8%
June 14, 2013June 12, 2013 ARE Sale $330,450 −8.9%−2.1%+0.9%
March 27, 2013March 25, 2013 ARE Sale $178,475 −9.6%−15.0%−16.9%
March 7, 2013March 5, 2013 ARE Sale $216,000 −12.2%−19.4%−18.4%
February 26, 2013February 22, 2013 ARE Sale $360,000 −9.6%−18.8%−19.8%
February 15, 2013February 13, 2013 ARE Sale $365,000 −1.2%−16.8%−19.7%
December 13, 2012December 11, 2012 ARE Sale $527,350 −6.7%−36.5%−35.9%
August 16, 2012August 14, 2012 ARE Sale $444,000 −6.0%−31.1%−33.2%
August 9, 2012August 7, 2012 ARE Sale $220,320 −8.0%−29.7%−26.7%
May 21, 2012May 17, 2012 ARE Sale $281,800 −0.8%−18.5%−16.5%
May 10, 2012May 8, 2012 ARE Sale $709,200 −5.9%−18.0%−18.6%
March 29, 2012March 27, 2012 ARE Sale $109,560 +3.0%−13.5%−11.8%
March 15, 2012March 13, 2012 ARE Sale $253,610 +1.1%−12.8%−13.9%
February 29, 2012February 27, 2012 ARE Sale $667,565 −0.4%−11.0%−9.3%
December 15, 2011December 13, 2011 ARE Sale $165,000 −4.2%−12.4%−8.3%
November 22, 2011November 18, 2011 ARE Sale $196,101 −3.6%−11.0%−12.5%
November 4, 2011November 2, 2011 ARE Sale $396,770 −1.6%−11.4%−9.0%
August 31, 2011August 31, 2011 ARE Sale $218,190 −10.6%−12.6%−12.7%
August 3, 2011August 1, 2011 ARE Sale $202,375 −11.4%−14.1%−16.3%
June 14, 2011June 10, 2011 ARE Sale $650,450 −4.4%−12.1%−11.7%
March 2, 2011February 28, 2011 ARE Sale $160,000 +3.5%−10.4%−13.8%
February 9, 2011February 7, 2011 ARE Sale $966,031 −2.5%−9.8%−6.9%
December 10, 2010December 8, 2010 ARE Sale $173,475 +7.5%−4.6%−3.9%
December 3, 2010December 1, 2010 ARE Sale $337,050 +4.5%−4.0%−6.3%
November 24, 2010November 22, 2010 ARE Sale $336,150 +6.9%−5.3%−3.4%
September 1, 2010August 30, 2010 ARE Sale $176,200 −14.8%−9.4%−11.6%
August 20, 2010August 18, 2010 ARE Sale $175,850 −12.6%−6.2%−6.2%
August 6, 2010August 4, 2010 ARE Sale $360,750 −7.6%−13.9%−5.4%
June 23, 2010June 21, 2010 ARE Sale $741,200 −3.8%−5.9%−5.7%
March 18, 2010March 16, 2010 ARE Sale $165,175 +13.7%+3.1%+4.5%
March 11, 2010March 9, 2010 ARE Sale $161,509 +14.6%+5.8%+5.1%
March 9, 2010March 5, 2010 ARE Sale $315,615 +9.5%+4.7%+6.0%

Open-market purchases and sales of at least $10,000 in companies we cover, from SEC Form 4 filings; sales made under a pre-set Rule 10b5-1 plan are not shown. “Not yet” means the window has not finished or the share price was under $5 at entry. These are the shares’ moves after each trade: they say nothing about why Marcus Joel S traded and do not suggest the use of non-public information. How every insider compares · the insider trading backtest.