Scams widely known as "Nigerian stings", well known from the mid-1990s, are spreading again through regular mail and email. As usual the scammers are targeting the business sector, with a special eye on wealthy individuals appearing on international mailing lists whose biographical data is easy to obtain.

But then and now, the scams are not limited to the well-to-do and ¿known. Several writers at TheMarker.com have also received sting letters (more details in a column appearing in TheMarker.com later this week.)

The Nigerian sting is a variation on a theme, where a given person receives a letter proposing a seemingly lucrative transaction. The letter proposes to use the addressee's bank account to deposit money, in exchange for which favor the account-holder will be lavishly recompensed.

The letters usually bear the logo of a legitimate-sounding company, such as Nigerian National Gas or South Africa Canning Company. The company says it wants to move money out of Nigeria to an account in the target nation, giving some plausible reason.

The addressee, the letter promises, gets to keep a portion of the deposited amount.

Moreover, the stings are usually very convincing: Upon demand the con-men can provide documentation complete with government or central bank stamps and signatures.

The purpose of the stings is always the same - to induce the patsy to pay preliminary fees and commissions, which on major sums can conceivably be in the hundreds or thousands. Feeling that the sums are insubstantial compared with the promised profits, the targets usually come through.

Coupled with the promise of easy money, the stings were often massively successful.

Stings began to hit Israelis in the mid-1990s, usually mentioning sums in the hundreds of millions of dollars ¿ generally touted to be the profits from government contracts. A year ago a new version hit the business community, centered on a "huge inheritance" that the unhappy heirs needed to smuggle out of wherever they pretended to be. The targets of this version were usually charities.