What the quick ratio is measuring
The quick ratio compares quick assets with current liabilities. Quick assets usually include cash, cash equivalents, marketable securities, and receivables, while inventory and prepaid expenses are excluded because they are less immediately available for liability coverage.
That makes the quick ratio a tougher test than the current ratio. Two companies can have the same current ratio but very different quick ratios if one relies heavily on inventory and the other holds more immediately liquid resources.