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MT

Matthew Tappin

STEM
PRESIDENT, ASSET MANAGEMENT · STEM, INC. · CIK 0001986259
FILING MIX · LIFETIME40%/60%
BUYS
25
SELLS
37
TOTAL VALUE
$601.7K
COMPANIES
1
ACTIVE SINCE
Dec 2023
HOLDINGS NOW
9,577
AVG SELL PX
$3.45
TRADE KIND
SHOWING 62 / 62
Trades · vs SPY
Loading price series…
Performance · forward returns vs SPY
20 backtested trades · 8 horizons · 22 pendingHow are these numbers computed? →
Forward-return performance of every backtestable P/S trade by Matthew Tappin, measured at 8 horizons from 7 days to 2 years. Deduped per economic event so co-filings count once. Excess return = trade return minus SPY return over the same window.
HORIZONTRADESWIN RATEINSIDER RETURNSPY RETURNMEAN EXCESSMEDIAN EXCESST-STAT
7d20+65.00%-6.07%-0.27%-5.79%-6.99%—
14d20+80.00%-11.03%-0.17%-10.86%-11.07%—
30d20+95.00%-16.82%-0.23%-16.59%-11.85%—
60d20+70.00%-12.30%+2.69%-15.00%-24.04%—
90d20+75.00%-19.02%+5.95%-26.84%-41.09%—
180d20(5 pending)+66.67%-29.23%+11.46%-40.69%-85.41%—
1y20(6 pending)+78.57%-47.91%+18.60%-70.57%-93.01%—
2y20(11 pending)+100.00%-75.65%+37.77%-115.08%-118.09%—
How to read this: Insider Returnis the average raw return of the filer's trades over the horizon. SPY Return is what SPY did over those same windows — reference only, not a comparison. The headline alpha number is Mean Excess = Insider − SPY; green means the filer beat SPY, red means they trailed it. Win rate is the share of individual trades where the filer beat SPY. T-statvalues above 2 mean the alpha is unlikely to be chance given the sample size. "Pending" counts trades where the horizon hasn't elapsed yet; their stats are not included in the row average.
Holdings over time
STEM · 9,577 shares · as of Jul 2, 2026
0116,610233,220349,829466,439202420252026SHARES HELD
Trading cadence · quarterly flow
BUY ● SELL ●
2023
2024
2024
2024
2024
2025
2025
2025
2025
2026
2026
2026
FLOW · 25 buys / 37 sellsCOVERAGE · 12 quarters
Form 4 filings · all activity
COMPANYTYPESHARESPRICEVALUEHELD AFTERTRADE DATEFILEDDETAILS
STEM
STEM, INC.
SALE
President, Software Products
996$7.85$7.8K9,577Jul 2, 2026Jul 2, 2026 ↗View →
STEM
STEM, INC.
PURCHASE
President, Software Products
2,750$7.81$21.5K10,573Jun 30, 2026Jul 2, 2026 ↗View →
STEM
STEM, INC.
SALE
President, Software Products
2,750——2,750Jun 30, 2026Jul 2, 2026 ↗View →
STEM
STEM, INC.
PURCHASE
President, Software Products
5,000$7.81$39.0K7,823Jun 30, 2026Jul 2, 2026 ↗View →
STEM
STEM, INC.
SALE
President, Software Products
5,000——5,000Jun 30, 2026Jul 2, 2026 ↗View →
STEM
STEM, INC.
SALE10b5-1
10b5-1 plan
402$10.83$4.4K2,823Mar 11, 2026Mar 13, 2026 ↗View →
STEM
STEM, INC.
SALE
President, Software Products
655$11.12$7.3K3,225Mar 10, 2026Mar 10, 2026 ↗View →
STEM
STEM, INC.
PURCHASE
President, Software Products
1,458——3,880Mar 7, 2026Mar 10, 2026 ↗View →
STEM
STEM, INC.
SALE
President, Software Products
1,458——1,459Mar 7, 2026Mar 10, 2026 ↗View →
STEM
STEM, INC.
SALE
President, Software Products
185$10.00$1.9K2,422Mar 4, 2026Mar 4, 2026 ↗View →
STEM
STEM, INC.
SALE
President, Software Products
300$9.67$2.9K2,607Mar 3, 2026Mar 4, 2026 ↗View →
STEM
STEM, INC.
PURCHASE
President, Software Products
670——2,907Mar 1, 2026Mar 2, 2026 ↗View →
STEM
STEM, INC.
SALE
President, Software Products
670——0Mar 1, 2026Mar 2, 2026 ↗View →
STEM
STEM, INC.
PURCHASEGRANT
Stock grant
17,200——17,200Feb 26, 2026Mar 2, 2026 ↗View →
STEM
STEM, INC.
PURCHASEGRANT
Stock grant
25,800——25,800Feb 26, 2026Mar 2, 2026 ↗View →
STEM
STEM, INC.
SALE
President, Software Products
366$11.40$4.2K2,237Feb 20, 2026Feb 23, 2026 ↗View →
STEM
STEM, INC.
SALE
President, Software Products
522$11.30$5.9K2,603Feb 19, 2026Feb 19, 2026 ↗View →
STEM
STEM, INC.
SALE
President, Software Products
1,253——0Feb 15, 2026Feb 18, 2026 ↗View →
STEM
STEM, INC.
PURCHASE
President, Software Products
1,253——3,125Feb 15, 2026Feb 18, 2026 ↗View →
STEM
STEM, INC.
SALE
President, Software Products
9,584$17.70$169.6K1,872Nov 11, 2025Nov 24, 2025 ↗View →
STEM
STEM, INC.
SALE
President, Software Products
5,416$18.27$99.0K11,456Nov 10, 2025Nov 12, 2025 ↗View →
STEM
STEM, INC.
SALE
President, Software Products
15,000——0Nov 7, 2025Nov 12, 2025 ↗View →
STEM
STEM, INC.
PURCHASE
President, Software Products
15,000——16,872Nov 7, 2025Nov 12, 2025 ↗View →
STEM
STEM, INC.
PURCHASEGRANT
Stock grant
10,000——10,000Jul 28, 2025Jul 30, 2025 ↗View →
STEM
STEM, INC.
PURCHASEGRANT
Stock grant
10,000——10,000Jul 28, 2025Jul 30, 2025 ↗View →
STEM
STEM, INC.
PURCHASEGRANT
Stock grant
11,000——11,000Jun 30, 2025Jul 2, 2025 ↗View →
STEM
STEM, INC.
PURCHASEGRANT
Stock grant
5,500——5,500Jun 30, 2025Jul 2, 2025 ↗View →
STEM
STEM, INC.
PURCHASEGRANT
Stock grant
5,500——5,500Jun 30, 2025Jul 2, 2025 ↗View →
STEM
STEM, INC.
SALE10b5-1
10b5-1 plan
20,823$0.45$9.4K37,458Jun 16, 2025Jun 18, 2025 ↗View →
STEM
STEM, INC.
SALE10b5-1
10b5-1 plan
1,164$0.45$52558,281May 30, 2025Jun 18, 2025 ↗View →
STEM
STEM, INC.
SALE
President, Software Division
2,775——396,784May 29, 2025Jun 18, 2025 ↗View →
STEM
STEM, INC.
PURCHASE
President, Software Division
2,775——59,445May 29, 2025Jun 18, 2025 ↗View →
STEM
STEM, INC.
SALE
President, Software Division
13,070$0.40$5.3K56,670Mar 12, 2025Mar 17, 2025 ↗View →
STEM
STEM, INC.
SALE
President, Software Division
29,167——399,559Mar 11, 2025Mar 17, 2025 ↗View →
STEM
STEM, INC.
PURCHASE
President, Software Division
29,167——69,740Mar 11, 2025Mar 17, 2025 ↗View →
STEM
STEM, INC.
SALE
President, Software Division
5,645$0.42$2.4K40,573Mar 7, 2025Mar 17, 2025 ↗View →
STEM
STEM, INC.
PURCHASE
President, Software Division
13,397——46,218Mar 6, 2025Mar 17, 2025 ↗View →
STEM
STEM, INC.
SALE
President, Software Division
13,397——428,726Mar 6, 2025Mar 17, 2025 ↗View →
STEM
STEM, INC.
SALE
President, Software Division
8,130$0.63$5.1K32,821Feb 20, 2025Feb 21, 2025 ↗View →
STEM
STEM, INC.
SALE
President, Software Division
24,316——442,123Feb 19, 2025Feb 21, 2025 ↗View →
STEM
STEM, INC.
PURCHASE
President, Software Division
24,316——40,951Feb 19, 2025Feb 21, 2025 ↗View →
STEM
STEM, INC.
PURCHASEGRANT
Stock grant
300,000——466,439Nov 1, 2024Nov 1, 2024 ↗View →
STEM
STEM, INC.
PURCHASEGRANT
Stock grant
87,500——166,439May 28, 2024May 28, 2024 ↗View →
STEM
STEM, INC.
SALE10b5-1
10b5-1 plan
1,388$1.32$1.8K16,635May 28, 2024May 30, 2024 ↗View →
STEM
STEM, INC.
SALE
President, Asset Management
2,775——78,939May 24, 2024May 28, 2024 ↗View →
STEM
STEM, INC.
PURCHASE
President, Asset Management
2,775——18,023May 24, 2024May 28, 2024 ↗View →
STEM
STEM, INC.
SALE
President, Asset Management
26,640$1.82$48.5K15,248Mar 19, 2024Mar 20, 2024 ↗View →
STEM
STEM, INC.
SALE10b5-1
10b5-1 plan
24,899$2.19$54.5K41,888Mar 8, 2024Mar 12, 2024 ↗View →
STEM
STEM, INC.
SALE10b5-1
10b5-1 plan
3,837$2.41$9.2K66,787Mar 5, 2024Mar 7, 2024 ↗View →
STEM
STEM, INC.
SALE
President, Asset Management
5,724$2.48$14.2K70,624Mar 4, 2024Mar 5, 2024 ↗View →
STEM
STEM, INC.
SALE
President, Asset Management
13,398——81,714Mar 1, 2024Mar 5, 2024 ↗View →
STEM
STEM, INC.
PURCHASEGRANT
Stock grant
51,539——76,348Mar 1, 2024Mar 5, 2024 ↗View →
STEM
STEM, INC.
PURCHASE
President, Asset Management
13,398——24,809Mar 1, 2024Mar 5, 2024 ↗View →
STEM
STEM, INC.
SALE
President, Asset Management
6,857$3.05$20.9K11,411Feb 20, 2024Feb 21, 2024 ↗View →
STEM
STEM, INC.
SALE
President, Asset Management
10,602$3.17$33.6K18,268Feb 16, 2024Feb 20, 2024 ↗View →
STEM
STEM, INC.
PURCHASEGRANT
Stock grant
45,024——45,024Feb 15, 2024Feb 20, 2024 ↗View →
STEM
STEM, INC.
SALE
President, Asset Management
24,315——95,112Feb 15, 2024Feb 20, 2024 ↗View →
STEM
STEM, INC.
PURCHASE
President, Asset Management
24,315——28,870Feb 15, 2024Feb 20, 2024 ↗View →
STEM
STEM, INC.
SALE
President, Asset Management
4,556$3.15$14.4K4,555Feb 14, 2024Feb 16, 2024 ↗View →
STEM
STEM, INC.
SALE
President, Asset Management
5,207$3.56$18.5K9,111Jan 3, 2024Jan 3, 2024 ↗View →
STEM
STEM, INC.
PURCHASE
President, Asset Management
14,318——14,318Dec 31, 2023Jan 3, 2024 ↗View →
STEM
STEM, INC.
SALE
President, Asset Management
14,318——119,427Dec 31, 2023Jan 3, 2024 ↗View →
Other insiders · STEM
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About this filer
CIK 0001986259
ROLE
President, Asset Management
PRIMARY
STEM
COMPANIES
1
ACTIVE SINCE
Dec 2023
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