Matthew Tappin - Insider Trading Tracker

Introduction

This page provides a comprehensive analysis of the known insider trading history of Matthew Tappin. Insiders are officers, directors, or significant investors in a company. It is illegal for insiders to make trades in their companies based on specific, non-public information. This does not mean it is illegal for them to make any trades in their own companies. However, they must report all trades to the SEC via a Form 4. Despite these restrictions, academic research suggests that insiders - in general - tend to outperform the market in their own companies.

Average Trade Profitability

Companies with Reported Insider Positions

The SEC filings indicate Matthew Tappin has reported holdings or trades in the following companies:

How to Interpret the Charts

The following charts show the stock performance of securities subsequent to each open-market, non-planned trade made by Matthew Tappin. Non-planned trade are trades that were not made as part of a 10b5-1 trading plan. The stock performance is charted as cumulative percent change in share price. For example, if an insider trade was made on January 1, 2019, the chart will show the daily percent change of the security to the present day. If the share price were to go from $10 to $15 during this time, the cumulative percent change in share price would be 50%. A change in price from $10 to $20 would be 100%, and a change in price of $10 to $5 would be -50%.

Ultimately, we are trying to determine how closely the insider’s trades correlate to excess returns (positive or negative) in the share price in order to see if the insider is timing their trades to profit from insider information. Consider the situation where an insider was doing this. In this situation, we would expect either (a) positive returns after purchases, or (b) negative returns after sales. In the case of (a), the PURCHASE chart would show a series of upwardly sloping curves, indicating positive returns after each purchase transaction. In the case of (b), the SALE chart would show a series of downward sloping curves, indicating negative returns after each sale transaction.

However, this alone is not enough to draw conclusions. If, for example, the share price of the company was in a non-cyclical climb over many years, then we would expect all the post-purchase plots to be upwardly sloping. Likewise, non-cyclical declines over many years would result in downward sloping post-trade plots. Neither of these charts would suggest insider trading activity.

The strongest indicator would be a situation where the share price was extremely cyclical, and there were both positive signals in the PURCHASE chart and negative plots on the SALE chart. This situation would be highly suggestive of an insider that was timing trades to their financial advantage.

Insider Purchases STEM / Stem, Inc. - Short Term Profit Analysis

In this section, we analyze the profitability of every unplanned, open-market insider purchase made in STEM / Stem, Inc.. This analysis helps to understand if the insider consistently generates abnormal returns, and is worth following. This analysis is for one-year following each trade, and the results are theoretical.

The following table shows the most recent open market purchases that were not part of an automatic trading plan.

Trade Date	Ticker	Insider	Reported Shares	Reported Price	Adjusted Shares	Adjusted Price	Cost Basis	Days to Max	Price at Max	Max Profit ($)	Max Return (%)
There are no known unplanned open-market trades for this insider and security combination

Adjusted Price is the split-adjusted price. Adjusted Shares is the split-adjusted shares.

Insider Sales STEM / Stem, Inc. - Short Term Loss Analysis

In this section, we analyze the short-term loss avoidance of every unplanned, open-market insider sale made in STEM / Stem, Inc.. A consistent pattern of loss avoidance may suggest that future sale transactions may predict declines in price. This analysis is for one-year following each trade, and the results are theoretical.

The following table shows the most recent open market sales that were not part of an automatic trading plan.

Trade Date	Ticker	Insider	Reported Shares	Reported Price	Adjusted Shares	Adjusted Price	Cost Basis	Days to Min	Price at Min	Max Loss Avoided ($)	Max Loss Avoided (%)
2025-05-30	STEM	Tappin Matthew	1,164	0.4510	58	9.0200	525	21	0.4182	-500	-95.37
2025-03-12	STEM	Tappin Matthew	13,070	0.4040	654	8.0800	5,280
2025-03-07	STEM	Tappin Matthew	5,645	0.4190	282	8.3800	2,365
2025-02-20	STEM	Tappin Matthew	8,130	0.6267	406	12.5340	5,095
2024-03-19	STEM	Tappin Matthew	26,640	1.8200	1,332	36.4000	48,485
2024-03-08	STEM	Tappin Matthew	24,899	2.1900	1,245	43.8000	54,529
2024-03-04	STEM	Tappin Matthew	5,724	2.4800	286	49.6000	14,196
2024-02-16	STEM	Tappin Matthew	10,602	3.1700	530	63.4000	33,608

Adjusted Price is the split-adjusted price. Adjusted Shares is the split-adjusted shares.

Insider Trading History

This table shows the complete list of insider trades made by Matthew Tappin as disclosed to the Securities Exchange Commission (SEC).