About 10 days ago, Liberty Media ( LINTA) Chairman John Malone sold $18 million worth of stock in Liberty Global ( LBTYA), a video and broadband service provider catering to Japan, Europe and Chile. Although Liberty Global's stock price is down 55% in the last month, you should follow his lead and get out now ahead of earnings, which will be announced in early November.Malone's multiple Liberty-related entities (e.g., Liberty Communications, Liberty Global, Discovery Communications ( DISCA)) have one thing in common: a love for opaque corporate structures with multiple classes of voting shares. In early 2007, before the words "CDS" and "subprime" had entered our collective lexicon, such complexity mattered little compared with high-growth businesses fueled by acquisitions. Liberty Global complied with this preference and its shares peaked at $44 in July 2007. However, there's been a slow descent since then until this month when the stock has fallen off a cliff. They traded yesterday under $13. Malone's large stock sales this month are not unique for corporate chiefs these days. Sumner Redstone of Viacom ( VIA) and CBS ( CBS) and Aubrey McClendon of Chesapeake ( CHK) both had to unload large amounts of shares in the face of margin calls a few weeks ago. Malone gave no explanation for his sale, although he presumably faced similar pressures, considering that Liberty Global had spent $1.621 billion repurchasing its shares in the first six months of this year at weighted prices between $34.37 and $35.55. That cash spent on share repurchases at triple the current market price could come back to harm Liberty Global in the coming quarters, as it only had $1.2 billion in cash at the end of June and just under $20 billion in debt.