# Calculating put-call ratio when volume is @0

So i have to do a put-call ratio plot. However i have to decide between using open interest and volume to calculate PCR. But in our data, the volume for some put/call options are 0. Is there a way to still calculate PCR with volume if it is @0?

Thanks.

• Sure, just divide by 0. Commented Oct 28, 2021 at 14:06
• One of my favorite Star Trek quotes from Q: "Easy; just change the gravitational constant of the Universe..." Commented Oct 28, 2021 at 15:58

Realistically, financial ratios are only useful to the extent that data is relatively 'normal'. If a financial ratio needs you to divide by zero given the data set, then that is a sign that the ratio is non-informative in this instance.

If you have an alternative ratio which is mathematically possible for the same data, then that ratio may be more informative.

Simple example to showcase what this looks like: let's say you want to calculate the value of buying a share of a mining company, considering the earnings-per-share relative to the current stock price [the Price to Earnings ratio]. Industry average for that ratio is, say, 10:1 (ie: a standard company in that industry could have \$500M annual earnings, and 1B shares outstanding each selling for \$5 each, which is a PE ratio of 5B/\$500M = 10:1). But your company doesn't HAVE earnings - it's a junior company with an incomplete mineshaft, funded largely by debt. Maybe it had a loss last year of \$10M in operating expenses, with 0 revenue, and say 5M shares outstanding, selling for \$3 each.

Does the ratio 15M/-\$10M = -\$.50 actually mean anything? What if its operating expenses perfectly offset its first year of revenue, leaving it with \$0 net earnings? Would 15M/0 actually mean anything? No, these are meaningless - and it should be understood that junior companies which don't yet have profit can't be evaluated using a PE ratio [similarly, Tesla's market cap of \$1T is not really a sign that the market is 'accepting' a PE ratio of 500:1, but more likely that 'the market', rightly or wrongly, assumes that future earnings from Tesla has little to do with current financial performance].

Instead of trying to force the data to 'work', understand that this is more a sign that the approach itself is inapplicable for your data.

A ratio is the comparison of two or more numbers by division. In this case, it's two numbers.

If one of the numbers is zero then you cannot determine the ratio and the data point must be either graphed as zero or ignored.