Estimates of the total losses due to the scam vary widely. The Snopes website lists the following estimate:

"The Nigerian scam is hugely successful. According to a 1997 newspaper article: "We have confirmed losses just in the United States of over $100 million in the last 15 months," said Special Agent James Caldwell, of the Secret Service financial crimes division. "And that's just the ones we know of. We figure a lot of people don't report them."

Although the "success rate" of the scam is hard to gauge, some experienced 419 scammers get one or two interested replies for every thousand messages. An experienced scammer can expect to make several thousand dollars per month.

Ultrascan Advanced Global Investigations, a Netherlands-based firm which has been studying 419 matters since the mid-1990s, has prepared a table quantifying 419 operations by country for 2005. These stats are based on Ultrascan's in-house investigations and include, by nation: number of 419 rings; number of 419ers; income of the 419ers (the amount of losses by victims to the 419ers); and additional data. 419 Coalition view is that these stats present a reasonably conservative and realistic look at the extent and magnitude of 419 criminal operations worldwide.

Since 1995, the United States Secret Service has been (somewhat) involved in combating these schemes, but they will not investigate unless the monetary loss is in excess of fifty thousand US Dollars. Very few arrests and prosecutions have been made due to the international aspect of this crime.