Guardant Health Shares Slide as Principal Cuts Stake and Insiders Sell

Guardant Health drew fresh attention after a new filing showed Principal Financial Group Inc. reduced its position, while separate data pointed to continued selling by corporate insiders. The stock traded around $107.58 in the update, near the Street’s average target of about $106.86, according to the figures cited in the report.

Principal trims stake as ownership stays institution heavy

Principal Financial Group cut its Guardant Health stake by 32.8% in the third quarter. It sold 86,006 shares and ended the period with 176,516 shares.

That remaining position was valued at about $11.03 million in the filing summary. The holding represented roughly 0.14% of Guardant Health.

Meanwhile, the same summary put institutional ownership at about 92.6%. Several firms also adjusted positions during the quarter, including new and expanded stakes.

Insider selling adds pressure signal

Recent insider transactions added another layer to the story. Over the past 90 days, insiders sold about 434,627 shares worth roughly $45.6 million, based on the figures provided.

The report highlighted sales by insider Terilyn J. Monroe and Chief Technology Officer Darya Chudova. Their disclosed transactions reduced their personal holdings after the sales.

Even after those sales, insiders still held about 6.10% of the company, according to the same source. That mix leaves institutions dominant, while insiders continued to reduce exposure.

Trend spike and quarterly flows show how attention shifted

A Google Trends showed “guardant health” rising in the United States over the past 24 hours. It listed 10,000-plus searches and a roughly 400% jump, with activity starting about 11 hours earlier.

Separately, a MarketBeat chart broke down institutional buying and selling by quarter. It showed outsized selling in Q1 2024 at about $5.65 billion, far above inflows near $146.7 million.

Guardant Health Institutional Buying and Selling by Quarter. Source: MarketBeat

The chart also showed another heavy outflow in Q4 2024 at about $3.95 billion, alongside inflows near $857.4 million. In later quarters, flows looked closer to balanced, including Q3 2025, with inflows near $839.8 million versus outflows near $822.6 million.