Jonathan Jay Mazelsky is CEO & President at IDEXX LABORATORIES INC /DE (IDXX). They have made 11 open-market trades across 1 company since 2020, most recently 2026-09-30.
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 11 sales. Too few scored purchases to measure a record yet.
| Ticker | Shares | Value |
|---|---|---|
| IDXX | 91,254 | $51.1M |
| XRAY | 61,668 | $528K |
| PODD | 1,496 | $211K |
| Total | $51.9M |
Shares reported on the most recent Form 4, priced at the 2026-10-02 close.
Counted per filing, not per execution lot — a purchase filled in several tranches is one decision.
| Ticker | Type | Traded | Filed | Price | Value | 7d Stock | 30d Stock | 90d Stock |
|---|---|---|---|---|---|---|---|---|
| IDXX | SELL | 2026-02-26 | 2026-03-02 | $657.55 | $15.3M | -9.0% | -10.1% | -9.7% |
| IDXX | SELL | 2025-08-06 | 2025-08-08 | $631.98 | $37.0M | -3.3% | -1.4% | +7.8% |
| IDXX | SELL | 2024-02-07 | 2024-02-09 | $572.61 | $13.7M | +0.4% | -3.6% | -12.0% |
| IDXX | SELL | 2023-12-04 | 2023-12-06 | $513.05 | $7.3M | +3.4% | +2.9% | +7.0% |
| IDXX | SELL | 2023-08-31 | 2023-09-05 | $512.01 | $13.7M | -8.0% | -12.2% | +5.4% |
| IDXX | SELL | 2022-11-14 | 2022-11-16 | $434.42 | $8.9M | -2.7% | -3.0% | +19.8% |
| IDXX | SELL | 2022-11-07 | 2022-11-09 | $382.94 | $8.8M | +3.0% | +4.9% | +26.6% |
| IDXX | SELL | 2021-08-13 | 2021-08-17 | $675.21 | $8.1M | -1.3% | -2.0% | -8.6% |
| IDXX | SELL | 2021-02-17 | 2021-02-19 | $537.15 | $14.6M | -9.0% | -10.2% | -1.4% |
| IDXX | SELL | 2020-11-05 | 2020-11-09 | $468.46 | $4.1M | +5.9% | +4.2% | +14.8% |
| IDXX | SELL | 2020-02-05 | 2020-02-07 | $277.82 | $4.4M | +1.3% | -12.6% | +5.9% |
Grouped by shared companies and similar filing behaviour. This is a similarity measure, not a ranking or a performance signal.