Please analyze the grammar

Richard X. Bove, an analyst at Punk Ziegel & Company, noted the trend in a recent note to investors and suggested that the reason was strong buying from portfolios that use computer models to buy and sell quickly, a practice known as program trading, or a foreign source like the investment arm of the Chinese government./quote]

Please analyze the grammar of the underlined part, and what does the analyst want to tell people to do exactly.