Check out the companies making headlines in midday trading: Visa — Shares dropped nearly 4% following a Bloomberg report that the Justice Department is preparing to file an antitrust lawsuit against the credit card network and payments processor. Smartsheet — Shares surged more than 6% after Blackstone and Vista Equity Partners agreed to buy the software maker for $56.50 a share in cash, or about $8.4 billion . Unless another offer is made, the deal is expected to close by January 2025, pending shareholder approval. China stocks — Shares of Chinese companies soared after China’s central bank unveiled a host of stimulus measures . E-commerce giants JD.com , PDD Holdings and Alibaba jumped between 7% and 11%, while automakers Nio and Li Auto each advanced more than 8% Thor Industries — The recreation vehicle stock climbed 5% after a stronger-than-expected earnings report. Thor earned $1.68 per share on $2.53 billion in revenue in its fiscal fourth quarter. Analysts surveyed by LSEG had penciled in $1.30 per share on $2.47 billion of revenue. Arlo Technologies — Shares popped 4.5% after the maker of wireless surveillance products, including security cameras and video doorbells, said its board approved a buyback of up to $50 million in common stock. Flowserve — The stock moved nearly 5% higher after Bank of America reiterated a buy rating, saying its exposure to nuclear power is “und …