Key TakeawaysReddit shares sank Friday on a report Advance Magazine Publishers planned to borrow against its stake in the social media platform.Regulatory filings also disclosed Chinese conglomerate Tencent Holdings sold shares.Other recent filings show that company insiders like CEO Steve Huffman have also sold shares. Reddit (RDDT) stock sank Friday on a report Advance Magazine Publishers planned to borrow against its stake in the social media platform and regulatory filings disclosed Chinese conglomerate ...