Director Orbimed Advisors LLC filed a Form 4 Code S (open-market sale) for $2.2M, reducing its stake by 1.6%. This is the first recorded open-market transaction by this director, with zero prior Code-P buys or Code-S sells on file. The sale at $44.61 occurred 4 days before earnings, with a consensus analyst rating of Strong Buy.

Where it could go — If the bear case holds, the stock may test the 90-day low of $32.56; the thesis is invalidated if the stock holds above the transaction price of $44.61 and the analyst consensus proves accurate.

Director Peter A. Thompson executed a Code-S open-market sale of 48,546 SION shares at $44.61 on 2026-05-07, reducing his stake by 1.6% and realizing $2.2M in proceeds. This is Thompson's first Form 4 filing on record, with no prior buy or sell history to establish a baseline trading pattern. The sale occurred 4 days before earnings (2026-05-11) with consensus EPS of -$0.52, while analyst consensus remains STRONG BUY (14 of 16 buy ratings); stock was 4% below the 90d high and 37% above the 90d low at transaction time.

Where it could go — If the earnings miss (consensus -$0.52) triggers analyst downgrades, the stock historically breaks below the $35.10 30d low; bull case requires the stock to hold above $44.61 and analyst consensus to remain STRONG BUY post-earnings, invalidating the insider-ahead-of-miss thesis.