What is the value of liquidity and its measures to investors and bankers? http://www.investopedia.com/articles/basics/07/liquidity.asp

The answer above discusses the two methods lenders (banks and other investors) use to calculate a company's liquidity ratio (the current ratio and the quick ratio), which indicates a company's ability to operate on a cash basis if required by company-specific or general market conditions.  The value of liquidity--from any perspective--is very straightforward: if a company cannot rely on its assets to generate daily operating funds, it must rely on its liquidity (that is, cash or cash equivalents).  An example of a "cash equivalent" is a letter of credit, usually from a AAA-rated lender, that can be used as cash if certain conditions exist.  

The meltdown experienced by the US economy in 2007-2008 was a great illustration of what happens when companies are asset rich and cash poor and then have to rely on liquidity because the asset base fails to generate sufficient income to operate a business or to make payments on its obligations.  As we saw during that period, many service-based financial companies like AIG, FGIC, MBIA, which had claim to billions of dollars of assets (mortgage-backed securities), did not have enough liquidity to pay their obligations as the real estate economy tanked much more quickly than any models predicted.

From a lender's perspective, most healthy companies have 7-10 days' worth of liquidity (again, cash or cash equivalents) to fund their operations.  In many cases, businesses that do not have liquid assets (e. g., real estate developers; insurance companies; financial guarantors) routinely line up liquidity providers like banks and other large institutional lenders, who, based on their assessment of the general credit-worthiness of the borrowing entity, provide liquidity lines of credit that can be drawn upon under certain conditions, and these liquidity lines provide the "operating cash" for companies whose assets may be be illiquid.

The ultimate problem with determining a company's liquidity is that the model for determining liquidity, like the models for determining how an asset class will perform, is based on historical performance of either the business type or the asset class.  If, however, historical performance becomes a poor predictor--as all models became between 2006 to 2010 in the US--what may seem to be adequate liquidity becomes laughably inadequate.