Four companies behind 44 million spam emails, 15 million nuisance calls and one million spam texts have been fined a total of £600,000.
Barrington Claims Limited, previously based in Llanelli but now registered in Port Talbot, has been fined £250,000 for making more than 15 million automated calls, and London-based Newday Limited must pay £230,000 for sending more than 44 million spam emails, the Information Commissioner's Office (ICO) said.
Goody Market UK Limited, in Liverpool, has been fined £40,000 for sending 111,367 spam texts and Macclesfield-based TFLI Limited has been fined £80,000 for sending 1.19 million nuisance texts.
The ICO said hundreds of complaints from the public prompted its investigations that found that all four firms had broken the law by not having people's agreement to be contacted by them.
Complaints were made about the frequency and persuasive nature of the calls, and included one from a householder just home from major hospital surgery who reported that the calls were "annoying and distressing as I have to have the phone free for district nurses and they are waking me up when I need to be sleeping".
Another complained: "I have a toddler and an autistic seven-year-old. Unwanted phone calls on the landline wake sleeping kids up, cause anxiety and can lead to my son becoming distressed. It's not OK."
Andy Curry, ICO enforcement group manager, said: "Firms cannot get away with failing to follow the rules designed to protect people from the irritation and, on occasions, distress nuisance calls, emails and texts cause.
"I would urge anyone bothered by nuisance marketing to report it to us. Your reports help us take action against firms like those we have fined today, putting a stop to the trouble they cause."
Nuisance calls and spam texts and emails can be reported via the ICO's website or by calling 0303 123 1113 with as much detail as possible.
Mobile phone users can also report spam texts by forwarding the message to 7726.