MARK STOLPER
CIK 1281961 · EVP, Chief Financial Officer · last filed 2026-07-29
"Disclosed insider exposure" sums this person's most-recently-reported share counts across each company they're an insider in, multiplied by the current underlying price. It is not net worth — it misses retail holdings, private investments, real estate, index funds, and any company where the person isn't an SEC-reporting insider. For informational purposes only.
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Disclosed Exposure
$9.60M
Companies
8
Total Filings
80
Lifetime Open-Market Net
-$6.35M
Holdings By Company
Latest on-record share count from this person's most recent non-derivative Form 4 transaction in each company. Disclosed exposure = shares × current underlying price.
| Symbol | Role | Shares | Price | Disclosed Exposure | Lifetime OM Net | Filings | Latest Filed |
|---|---|---|---|---|---|---|---|
| TOI | Director | 56,957 | $5.13 | $292.2K | $0 | 2 | 2026-07-29 |
| RDNT | EVP, Chief Financial Officer | 121,943 | $76.34 | $9.31M | -$5.07M | 26 | 2026-03-05 |
| CHRS | Director | — | $1.21 | — | $0 | 6 | 2024-06-05 |
| SURGALIGN HOLDINGS, INC. (SRGA) Delisted | Director | 28,867 | $0.18 | $5.3K | $25.0K | 4 | 2022-08-17 |
| RTI SURGICAL, INC. (RTIX) Delisted | Director | 0 | — | — | $22.9K | 6 | 2019-03-11 |
| RadNet, Inc. (ROIAK) Delisted | Executive VP and CFO | 170,319 | — | — | -$1.34M | 25 | 2017-01-09 |
| Star Equity Holdings, Inc. (HSON) Delisted | 50 | $9.88 | $494 | $1.3K | 1 | 2014-10-21 | |
| METROPOLITAN HEALTH NETWORKS INC (MDF) Delisted | Director | 37,232 | — | — | $0 | 5 | 2012-06-13 |
Recent Filings · Page 8 of 8
80 filingsInsider activity across all companies, newest first. Form 4 rows are post-trade confirmations (buys, sells, grants, exercises). Notice (144) rows are pre-trade notices of intent to sell restricted or control stock under Rule 144 — they may not all execute. Compare adjacent dates to see which notices became actual sales.
| Filed | Symbol | Action | Net Shares | Net $ | Link |
|---|---|---|---|---|---|
| 2010-06-09 | RadNet, Inc. (ROIAK) Delisted | Other (J) | — | $0 | EDGAR |
| 2010-04-28 | METROPOLITAN HEALTH NETWORKS INC (MDF) Delisted | Grant (A) | +11,978 | $0 | EDGAR |
| 2009-09-22 | RadNet, Inc. (ROIAK) Delisted | Sell (S) | −22,200 | -$52.4K | EDGAR |
| 2009-09-21 | RadNet, Inc. (ROIAK) Delisted | Sell (S) | −77,800 | -$181.6K | EDGAR |
| 2009-09-21 | RadNet, Inc. (ROIAK) Delisted | Sell (S) | −69,215 | -$164.7K | EDGAR |
| 2009-09-18 | RadNet, Inc. (ROIAK) Delisted | Sell (S) | −30,785 | -$72.3K | EDGAR |
| 2009-07-30 | RadNet, Inc. (ROIAK) Delisted | Mixed | +260,000 | $0 | EDGAR |
| 2009-06-17 | RadNet, Inc. (ROIAK) Delisted | Other (J) | — | $0 | EDGAR |
| 2009-02-27 | RadNet, Inc. (ROIAK) Delisted | Mixed | +12,805 | $0 | EDGAR |
| 2008-10-30 | RadNet, Inc. (ROIAK) Delisted | Other (J) | — | $0 | EDGAR |
Showing 71–80 of 80
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Page 8 of 8
Form 4 codes: P = open-market purchase · S = open-market sale · A = grant/award · M = option exercise · F = tax withholding at vest · G = bona-fide gift · D = disposition to issuer · J = other (see filing footnote). Only P / S codes carry directional signal.
Notice (144 / 144/A): Form 144 is a notice of intent to sell restricted/control stock under Rule 144, filed before the sale; 144/A is an amendment. Many notices are pre-scheduled under Rule 10b5-1 plans. A Form 4 with code S typically follows within a few days when the planned sale executes; missing follow-up Form 4s suggest the notice was cancelled or modified.
Notice (144 / 144/A): Form 144 is a notice of intent to sell restricted/control stock under Rule 144, filed before the sale; 144/A is an amendment. Many notices are pre-scheduled under Rule 10b5-1 plans. A Form 4 with code S typically follows within a few days when the planned sale executes; missing follow-up Form 4s suggest the notice was cancelled or modified.