NEW YORK (AP) -- Four more Internet service providers will start charging banks, e-commerce sites and other large e-mail senders for guaranteed delivery.

In deals expected to be announced Thursday, Goodmail Systems Inc. is expanding its CertifiedEmail program to Comcast Corp., Cox Communications Inc., Time Warner Cable Inc.'s Road Runner and Verizon Communications Inc. Yahoo Inc. and Time Warner Inc.'s AOL became inaugural participants last year.

Individuals, businesses and organizations will be able to continue sending messages for free, but they risk finding those missives caught in increasingly aggressive spam filters.

With Goodmail, a company can pay a quarter of a penny per message to bypass those filters and reach inboxes directly. Recipients see a blue seal verifying that the message is legitimate; senders get confirmations and can resend messages lost in transit.

Non-profit groups can participate, too, at about a tenth of the commercial rates.

At least half of the fees go to the service provider, Goodmail Chief Executive Richard Gingras said.

For now, Goodmail will approve only companies and organizations in existence for at least a year, to thwart fly-by-night operations. Those that have prompted too many spam complaints will be disqualified.

The service is designed to certify credit card statements, e-commerce receipts and other communications with existing customers. It does potentially give a boost to larger corporations and groups that can afford the charge, but Gingras says their messages are the ones most likely to be mischaracterized as junk.

Peter Castleton, Verizon's director of consumer broadband services, said his company would still let senders apply for ''whitelisting'' -- and thus bypass filters as well -- without charge. Goodmail's service, he said, is for those that want approval at multiple ISPs at once.