Mark C. Biderman is Director at Apollo Commercial Real Estate Finance, Inc. (ARI). They have made 16 open-market trades across 4 companies since 2010, most recently 2026-04-01.
Unrated. We grade insiders only on stock they chose to buy on the open market. Grants, option exercises and vesting say nothing about timing, so they don't count — which is why someone can file often and still have no grade. It isn't a bad sign: unrated buys beat every graded tier below A.
7 open-market purchases totalling $448K since 2010, against 9 sales. Too few scored purchases to measure a record yet.
| Ticker | Type | Traded | Filed | Price | Value | 7d Stock | 30d Stock | 90d Stock |
|---|---|---|---|---|---|---|---|---|
| ARI | SELL | 2025-04-29 | 2025-05-01 | $9.48 | $95K | +5.0% | +3.1% | +2.4% |
| ARI | SELL | 2024-05-01 | 2024-05-02 | $10.00 | $150K | -0.9% | -1.4% | +5.3% |
| ARI | SELL | 2023-09-06 | 2023-09-08 | $10.60 | $106K | +0.0% | -5.5% | +3.2% |
| ARI | SELL | 2022-05-17 | 2022-05-19 | $12.68 | $127K | +3.9% | -15.9% | +5.7% |
| ARI | SELL | 2021-04-26 | 2021-04-28 | $14.96 | $105K | -1.7% | +2.2% | +0.7% |
| ARI | SELL | 2018-12-07 | 2018-12-10 | $18.85 | $189K | -9.1% | -5.8% | -2.0% |
| ARI | SELL | 2018-08-27 | 2018-08-29 | $19.45 | $195K | +0.1% | -2.9% | -3.3% |
| ARI | SELL | 2018-02-20 | 2018-02-22 | $18.48 | $185K | +1.0% | -0.8% | +1.1% |
| ARI | SELL | 2017-03-02 | 2017-03-06 | $18.23 | $273K | +0.3% | +3.3% | +1.8% |
| FULL | BUY | 2015-04-07 | 2015-04-08 | $3.50 | $40K | N/A | N/A | N/A |
| FULL | BUY | 2014-09-22 | 2014-09-24 | $6.19 | $27K | N/A | N/A | N/A |
| ARI | BUY | 2011-11-11 | 2011-11-15 | $13.90 | $70K | -4.5% | -1.4% | -1.4% |
| AMTG | BUY | 2011-11-11 | 2011-11-15 | $15.59 | $78K | N/A | N/A | N/A |
| ATLS | BUY | 2011-08-23 | 2011-08-25 | $18.78 | $146K | -47.4% | -8.0% | -8.0% |
| ATLS | BUY | 2011-08-10 | 2011-08-12 | $19.67 | $43K | -47.4% | -8.0% | -8.0% |
| FULL | BUY | 2010-09-01 | 2010-09-03 | $8.80 | $44K | N/A | N/A | N/A |
Grouped by shared companies and similar filing behaviour. This is a similarity measure, not a ranking or a performance signal.