Stocks making the biggest moves after hours: Chubb, Cisco Systems, Palo Alto Networks and more

Check out the companies making headlines in extended trading. Chubb — The property and casualty insurer gained nearly 6% after Berkshire Hathaway revealed it has bought nearly 26 million shares of Zurich-based company for a stake worth $6.7 billion. Chubb became Berkshire's ninth biggest holding at the end of March, according to a new regulatory filing. AST SpaceMobile — Shares rocketed 33%. AST SpaceMobile announced a commercial agreement with AT & T to bring its space-based broadband network direct to everyday cell phones. AT & T shares were little changed. The company also posted a narrower-than-expected loss of 16 cents per share for the first quarter, compared to a 23 cent loss per share in the year-ago period. Cisco Systems — Shares jumped nearly 5% after the IT giant reported fiscal third-quarter adjusted earnings of 88 cents per share on revenues of $12.70 billion. The results topped analysts' estimates for earnings of 82 cents per share on revenues of $12.53 billion, according to LSEG. B. Riley Financial — The Los Angeles-based middle-market investment bank fell 2% after losing $1.71 per share in the first quarter, reversing year earlier net income of 51 cents. Riley, which received a Nasdaq delinquency notice in March, left its quarterly dividend at 50 cents a share after halving it in February . Hawkins — The Minnesota-based chemical maker dropped 6% after fiscal fourth quarter sales fell 2% from the year-earlier period. Management warned about its industrial business in the next 12 months, saying "We are cautiously optimistic about our Industrial segment, but we believe economic and competitive pressures will continue to weigh on many of our customers and impact demand." Palo Alto Networks — The cybersecurity company saw its stock rise 1% after announcing it will buy cloud security software assets from IBM . The move is part of a broader partnership, giving Palo Alto access to more consultants and a bigger customer base. IBM shares were little changed. — CNBC's Scott Schnipper contributed reporting