Mark C. Thurmond is COO at Tenable Holdings, Inc. (TENB). They have made 24 open-market trades across 1 company since 2022, most recently 2026-08-24.
CIK 0001651579
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.
0 open-market purchases, against 24 sales. Too few scored purchases to measure a record yet.
| Ticker | Type | Traded | Filed | Price | Value | 7d Stock | 30d Stock | 90d Stock |
|---|---|---|---|---|---|---|---|---|
| TENB | SELL | 2025-08-26 | 2025-08-27 | $29.84 | $152K | +0.4% | -3.3% | -13.5% |
| TENB | SELL | 2025-08-25 | 2025-08-26 | $30.25 | $862K | +4.6% | -0.8% | -13.8% |
| TENB | SELL | 2025-05-27 | 2025-05-29 | $32.45 | $161K | +0.6% | +4.9% | -5.0% |
| TENB | SELL | 2025-05-23 | 2025-05-27 | $31.98 | $357K | +1.5% | +2.7% | -7.4% |
| TENB | SELL | 2025-02-26 | 2025-02-28 | $38.17 | $829K | -5.1% | -8.3% | -15.7% |
| TENB | SELL | 2025-02-25 | 2025-02-26 | $38.48 | $278K | -4.7% | -8.0% | -14.2% |
| TENB | SELL | 2025-02-19 | 2025-02-20 | $39.56 | $106K | -2.1% | -6.4% | -17.5% |
| TENB | SELL · 10b5-1 | 2024-11-27 | 2024-12-02 | $42.95 | $40K | +2.6% | -7.1% | -10.2% |
| TENB | SELL · 10b5-1 | 2024-11-26 | 2024-11-27 | $42.57 | $254K | +2.3% | -5.9% | -7.8% |
| TENB | SELL | 2024-11-25 | 2024-11-26 | $42.74 | $200K | +0.1% | -5.2% | -10.1% |
| TENB | SELL · 10b5-1 | 2024-11-20 | 2024-11-22 | $40.71 | $34K | +1.6% | -4.4% | -9.9% |
| TENB | SELL | 2024-11-19 | 2024-11-20 | $40.72 | $180K | +3.4% | +0.0% | -3.5% |
| TENB | SELL · 10b5-1 | 2024-08-26 | 2024-08-28 | $41.60 | $284K | -5.3% | -3.0% | +4.5% |
| TENB | SELL | 2024-08-23 | 2024-08-26 | $41.54 | $196K | -4.7% | -3.2% | +4.2% |
| TENB | SELL · 10b5-1 | 2024-08-21 | 2024-08-22 | $42.17 | $34K | -4.9% | -4.4% | -2.7% |
| TENB | SELL | 2024-08-20 | 2024-08-21 | $42.36 | $188K | -6.4% | -5.7% | -4.7% |
| TENB | SELL · 10b5-1 | 2024-07-30 | 2024-08-01 | $49.01 | $230K | +1.8% | -1.4% | +1.4% |
| TENB | SELL · 10b5-1 | 2024-05-28 | 2024-05-29 | $43.97 | $42K | -3.2% | +2.6% | -3.9% |
| TENB | SELL · 10b5-1 | 2024-05-23 | 2024-05-28 | $43.30 | $460K | -4.4% | +1.4% | -2.1% |
| TENB | SELL · 10b5-1 | 2024-05-21 | 2024-05-23 | $43.55 | $36K | -3.9% | -5.6% | -0.5% |
| TENB | SELL | 2024-05-20 | 2024-05-21 | $43.76 | $194K | -5.4% | -9.9% | -1.7% |
| TENB | SELL · 10b5-1 | 2024-03-20 | 2024-03-22 | $49.00 | $530K | -1.9% | -7.0% | -19.2% |
| TENB | SELL · 10b5-1 | 2024-02-27 | 2024-02-29 | $47.13 | $671K | -2.5% | +2.5% | -11.6% |
| TENB | SELL | 2024-02-23 | 2024-02-27 | $47.71 | $839K | -0.6% | +5.5% | -8.3% |
| TENB | SELL · 10b5-1 | 2024-02-21 | 2024-02-22 | $47.13 | $171K | -3.9% | +2.2% | -8.4% |
Grouped by shared companies and similar filing behaviour. This is a similarity measure, not a ranking or a performance signal.