Chirfi Guindo is Head of Glob Prod Strat & Com at BIOGEN INC. (BIIB). They have made 6 open-market trades across 2 companies since 2021, most recently 2026-08-13.
CIK 0001722753
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 6 sales. Too few scored purchases to measure a record yet.
| Ticker | Shares | Value |
|---|---|---|
| MRK | 36,613 | $5.3M |
| BIIB | 8,243 | $1.9M |
| Total | $7.3M |
Shares reported on the most recent Form 4, priced at the 2026-08-13 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 |
|---|---|---|---|---|---|---|---|---|
| MRK | SELL | 2026-08-13 | 2026-08-13 | $135.00 | $1.4M | +16.6% | +8.0% | — |
| MRK | SELL | 2026-08-06 | 2026-08-07 | $131.00 | $2.0M | +18.5% | +15.6% | — |
| MRK | SELL | 2026-02-12 | 2026-02-12 | $121.46 | $1.2M | +0.8% | -5.0% | -6.6% |
| MRK | SELL | 2026-02-09 | 2026-02-09 | $118.41 | $1.2M | +3.9% | -1.3% | -5.4% |
| MRK | SELL | 2026-02-05 | 2026-02-06 | $121.88 | $2.4M | +0.4% | -3.5% | -7.5% |
| BIIB | SELL | 2021-06-07 | 2021-06-09 | $440.00 | $1.4M | -6.4% | -12.0% | -19.6% |
Grouped by shared companies and similar filing behaviour. This is a similarity measure, not a ranking or a performance signal.