Insider · CIK 0001281961
Mark Stolper
Files at RDNT (RadNet, Inc.), CHRS (Coherus BioSciences, Inc.), STLN (Oncology Institute, Inc.). First filing Jun 12, 2024, latest Sep 18, 2025.
In brief
Mark Stolper files SEC Form 4 as CFO and director at RDNT (RadNet, Inc.), and also at CHRS (Coherus BioSciences, Inc.), STLN (Oncology Institute, Inc.). Since Jun 12, 2024, Mark Stolper has reported 0 open-market buys worth $0 and 2 open-market sells worth $4.1M, the latest filed on Sep 18, 2025.
A track record needs three past buys with six months of prices behind them; Mark Stolper has 0, so none is measured yet.
The newest scored trade: sold $2.6M of RDNT on Sep 16, 2025, filed Sep 18, 2025, scored 72 (notable).
Where the trades landed
Last year at the company this insider has traded most, with each buy and sell on the bar it happened.
RDNT: RadNet, Inc.
Daily candles, adjusted for splits and dividends. Green arrows are insider buys, red are sells, sized by value. Click a marked bar to open the signal.Charts by TradingView Lightweight Charts™
Signals
This insider’s open-market buys and sells, scored.
| Score | Company | Value | Holdings | Price context | Filed |
|---|---|---|---|---|---|
| 72Notable | RadNet, Inc. | $2.6M 35,000 shares | -34% | +62% from low-14% from high | |
| 67Notable | RadNet, Inc. | $1.5M 25,000 shares | -24% | +142% from low0% from high |
Planned sales
Form 144 notices this insider filed before selling restricted or control stock, newest first.
| Filed | Company | Shares | Value | Sale date | Past 3 months |
|---|---|---|---|---|---|
| Sep 15, 2025 | RDNT RadNet, Inc. | 35,000 0.05% of outstanding | $2.6M | Sep 15, 2025 | none |
| Jun 10, 2024 | RDNT RadNet, Inc. | 25,000 0.03% of outstanding | $1.5M | Jun 10, 2024 | none |
Transactions
Every row this insider has filed, 12 in all, newest first.
| Date | Company | Transaction | Shares | Price | Value | Holdings after | Filed |
|---|---|---|---|---|---|---|---|
| Jul 27, 2026 | STLN Oncology Institute, Inc. | AGrant or award Common Stock | +31,124 | $0.00 | $0 | 56,957 | Jul 29, 2026 |
| Jul 7, 2026 | STLN Oncology Institute, Inc. | AGrant or award Common Stock | +25,833 | $0.00 | $0 | 25,833 | Jul 9, 2026 |
| Mar 3, 2026 | RDNT RadNet, Inc. | AGrant or award Common Stock | +18,228 | $0.00 | $0 | 121,943 | Mar 5, 2026 |
| Dec 10, 2025 | RDNT RadNet, Inc. | MOption exercise Common Stock | +35,703 | $6.07 | $217k | 103,715 | Dec 12, 2025 |
| Dec 10, 2025 | RDNT RadNet, Inc. | MOption exercise Employee Stock Option (right to buy)derivative | -35,703 | $0.00 | $0 | 0 | Dec 12, 2025 |
| Sep 16, 2025 | RDNT RadNet, Inc. | SOpen-market sale Common Stock | -35,000 | $73.89 | $2.6M | 68,012 | Sep 18, 2025 |
| Dec 16, 2024 | RDNT RadNet, Inc. | GGift Common Stock | -275 | $0.00 | $0 | 80,123 | Dec 18, 2024 |
| Jun 10, 2024 | RDNT RadNet, Inc. | SOpen-market sale Common Stock | -25,000 | $61.27 | $1.5M | 80,398 | Jun 12, 2024 |
| Jun 3, 2024 | CHRS Coherus BioSciences, Inc. | AGrant or award Stock Option (Right to Buy)derivative | +112,000 | $0.00 | $0 | 112,000 | Jun 5, 2024 |
| Mar 1, 2024 | RDNT RadNet, Inc. | AGrant or award Common Stock | +14,072 | $0.00 | $0 | 105,398 | Mar 4, 2024 |
| Mar 1, 2024 | RDNT RadNet, Inc. | AGrant or award Employee Stock Option (right to buy)derivative | +27,276 | $0.00 | $0 | 27,276 | Mar 4, 2024 |
| Jan 9, 2024 | RDNT RadNet, Inc. | AGrant or award Restricted Stock Unitsderivative | +14,558 | $0.00 | $0 | 14,558 | Jan 10, 2024 |
Questions about Mark Stolper
Answered from the filings on this page, as of the latest one.
Is Mark Stolper buying or selling?
Not in the last 12 months. Mark Stolper's latest open-market trade on SEC Form 4 was sold $2.6M of RDNT on Sep 16, 2025.
How did Mark Stolper's past buys perform?
Not measured yet. InsiderTell needs three past buys with six months of prices to publish a track record, and Mark Stolper has 0.
Where does Mark Stolper file Form 4?
Mark Stolper has filed Form 4 at RDNT (RadNet, Inc.) as EVP, Chief Financial Officer; CHRS (Coherus BioSciences, Inc.); STLN (Oncology Institute, Inc.). A Form 4 is required of officers, directors and holders of more than 10% of a share class within two business days of a trade.
Not investment advice. Scores and forward returns are decision support built from public SEC filings and past prices; they describe what happened after comparable filings, not what will happen after this one. Do your own research and size your risk.