Summary
Updated Aug 30, 2026
WINMILL CO. INC files SEC Form 4 reports at Global Self Storage, Inc. (SELF). 41 SEC Form 4 filings on record going back to 2025, most recently on 26 August 2026. Most recent open-market trade: bought $44K of SELF on 26 August 2026. Lifetime open-market purchases: $3.68M. Historical track record: 3/5 stars across 36 tracked purchases.
Recent Transactions
20Every recent SEC Form 4 transaction WINMILL CO. INC has reported, most recent first.
Track Record
InsiderAlpha computes a forward-return-based score for every insider with enough Form 4 purchase history. The metrics below reflect realized performance after each tracked open-market purchase.
| Metric | Value |
|---|---|
| InsiderAlpha rating | ★★★☆☆ (3/5) |
| Total purchases tracked | 36 |
| Purchases with forward-return data | 36 |
| 30-day win rate | 42% |
| 90-day win rate | 50% |
| Avg 5-day return | +0.54% |
| Avg 30-day return | -0.40% |
| Avg 90-day return | +2.67% |
| Best 30-day return | +4.96% |
Trading Pattern
InsiderAlpha's records for WINMILL CO. INC go back to 2025: 41 primary Form 4 filings, an average of 20.5 per year. The typical open-market purchase is $50K (74 buys totaling $3.68M). The largest single buy on record is $136K of BXSY in 2025. No transaction on record carries a Rule 10b5-1 flag - the filings look discretionary rather than pre-scheduled, which makes their timing more informative as a signal.
Other Insiders Active in the Same Stocks
Insiders who reported open-market trades in the last 12 months at the companies WINMILL CO. INC files at. Multiple unrelated insiders buying the same stock within a short window, cluster buying, has historically been one of the strongest Form 4 signals.
- Mark Campbell Winmill - $105K of SELF open-market activity in the last 12 months
- Roger A. Atkinson - $80K of BXSY open-market activity in the last 12 months
- William McCollum Winmill - $14K of BXSY open-market activity in the last 12 months
- Russell E. Burke III - $8K of SELF open-market activity in the last 12 months
- Donald Klimoski II - $2K of SELF open-market activity in the last 12 months
More Notable Insiders
Other corporate insiders with significant SEC Form 4 track records on InsiderAlpha:
Frequently Asked Questions
What is WINMILL CO. INC?
WINMILL CO. INC is a corporate entity of Global Self Storage, Inc. (SELF). InsiderAlpha holds 41 primary Form 4 filings for it, the earliest from 2025, updated as new SEC EDGAR filings are processed.
How many SEC Form 4 filings has WINMILL CO. INC submitted recently?
21 primary Form 4 filings in the last 90 days, covering 2 companies.
Has WINMILL CO. INC been buying or selling stock?
Recorded transactions: 74 open-market purchases ($3.68M) and 0 open-market sales across all tracked filings.
How accurate is WINMILL CO. INC's historical track record?
Across 36 tracked purchases, WINMILL CO. INC averaged -0.4% avg 30-day return with a 42% 30-day win rate. InsiderAlpha rates the track record at 3/5 stars.
Where can I see all of WINMILL CO. INC's SEC filings?
All Form 4 filings, transaction values, and 10b5-1 plan flags are listed on this page and updated in real time as new SEC EDGAR filings are processed.
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