It's an expensive lesson on the importance of reading your mail.

A Wisconsin judge has ordered PepsiCo Inc to pay $1.26 billion to two men who said it stole their idea to sell purified water after a secretary mislaid a document alerting the world's No. 2 soft drink maker the lawsuit existed.

The case was reported earlier on Wednesday by The National Law Journal. The judgment amount is equal to more than 20 percent of PepsiCo's reported annual profits in recent years, regulatory filings show.

According to filings with the Jefferson County Circuit Court, Charles Joyce and James Voigt won the September 30 judgment five months after first suing PepsiCo and two distributors.

The Wisconsin men said they talked with the distributors in 1981 about their idea to bottle and sell purified water and that PepsiCo later stole the idea by creating Aquafina.

The complaint was filed on April 28, but PepsiCo said the legal department at its Purchase, New York headquarters was not alerted to the case until around September 18, when secretary Kathy Henry received a letter for her supervisor Tom Tamoney.

Henry, however, put the letter aside and did not tell anyone about it or enter it into her log "because she was so busy preparing for a board meeting," according to PepsiCo's October 13 motion asking the court not to enforce the judgment.