The Net Debt to Price Ratio is the inverse of the Price to Net Debt Ratio. This figure is computed from the latest available interim accounts.
This measure gives a sense of how indebted a company is relative to its market value. Many companies are valued on the basis of their Enterprise Value, which incorporates debt. If the valuation moves suddenly due to a change in circumstances, the only portion of the EV which can quickly revalue is the Equity portion. Therefore, companies which have a high debt to market capitalisation ratio can have volatile valuations, especially if trading is difficult.
As with all of our Balance Sheet Ratios, this will be based on the latest financial statements (interim or annual) but it's always important to be aware of any post-balance sheet events that may have reduced the cash balance - an acquisition or a buyback, for example. The market may be pricing in something that has not been captured by the snapshot given in the latest financial statements.