Soitec Shares Plunge 4.5%, Lagging Behind in SBF 120 After a Grim Month
The Isère-based semiconductor substrate specialist wipes out its previous day's rebound and ends up at the bottom of the broad Paris index. The stock plunges below a closely watched technical threshold, illustrating the extreme volatility of the stock, even as the Paris market shows a significant uptick.
The stock breaks its support at €116.50 again, ending up at the bottom of the SBF 120
Soitec's shares fell by 4.59% to €111.30, down from €116.65 the previous day. The stock has significantly dropped below its support level of €116.50, which had been tested several times in recent sessions, marking the steepest decline in the SBF 120, while the index itself rose by 0.69%. This drop contrasts with a still positive weekly sequence (+3.7% over seven days), but is part of a challenging month, marked by a nearly 24% decline. However, the quarterly performance remains spectacular, at over 100%, a legacy of the spring rally.
The price is now 22% below its MM20 (€142.93) and 19% under its MM50 (€136.89), indicating a clear detachment from the short-term momentum. Only the MM200, at €61.74, remains significantly distanced by the price, reminding of the substantial progress made over a year (+140%). The RSI at 44 does not yet indicate a marked overselling, which leaves the door open for a continuation of the movement if the breached support turns into resistance.
A digested Chinese partnership, in a more fragile macro and sectoral environment
Today's movement comes after a turbulent period surrounding the partnership formed with the Chinese foundry ZenSemi on 300 mm BCD-on-SOI substrates, announced on June 29. The initial enthusiastic reception has given way to profit-taking, in a semiconductor sector that remains sensitive to signals from Asia. On the macro side, the Chinese non-manufacturing PMI fell back into contraction territory in April (49.4) and the OECD leading indicator continues to trend below, both benchmarks weighing on stocks exposed to the Chinese industrial cycle.
During the annual release on May 27, 2026, the company highlighted the ramp-up of Photonics-SOI solutions for data centers and demand related to artificial intelligence, while pointing out the risks of inventory corrections among customers and pressure on profitability due to lower volumes. This context remains the main framework for interpreting recent movements. The next concrete milestone: whether or not the support at €116.50 will be breached at closing, a threshold already broken several times and which has become the technical reference for the stock.
