If you're like us, you like reading comics as soon as they're available. But as it turns out, some comic stores are selling comics before they should officially go on-sale.

Marvel Comics sent out a strongly-worded warning to retailers on Thursday, July 20, threatening to delay the store(s) comic shipments until after the scheduled release date if they're caught doing it.

"In our efforts to ensure on-time deliveries around holidays and other potential supply chain disruptions, there are instances where product will deliver earlier than expected," reads the unsigned note from Marvel. "Please note that this product cannot be sold until the stated on-sale date. Any accounts found to be in repeated violation of breaking the on-sale date will be at risk of no longer receiving product prior to release. We thank you for your cooperation."

In the past, comics publishers and distributors have used various methods including secret shoppers to determine if stores are breaking release dates in terms of selling comics.

Does your store ever sell comics early? Tell us in the comments.

Have you read all your new comics? Make sure you've read all the classics from our guide to the best Marvel Comics stories of all time.