Amazon.com ( AMZN) was losing ground before the bell Monday after The Wall Street Journal reported that an annual report filed last week with the Securities and Exchange Commission revealed that the company has pledged $166.7 million of its marketable securities as collateral for certain financial obligations. In Instinet trading before the opening bell, Amazon was dropping 6.9% to $12.78 and was one of the top volume movers. The report doesn't say when the securities were pledged. The obligations consist mostly of property leases that aren't on Amazon's balance sheet. Investors bid down the stock because they feared that the report will raise questions about the company's liquid assets. Amazon's liquidity has been a source of debate for several months, but the company's latest quarterly report seemingly put those concerns to rest.