How am I being sent this spam?

Factual Questions
#1

I have an email account that came as part of the business broadband package at my place of work; I have never used it even once to send a message and I only check it from time to time to see if there’s an administrative notice or a payment reminder or some such.

Then quite recently, I signed up for an online stock/share dealing account (with barclays - a quite reputable bank); starting the next day, I began receiving lots and lots of spam, all of it about shares that I might be interested in buying, or, if the messages are to be believed (i.e. not), stockmarket investment opportunities that i would be insane to miss.

OK, it’s only spam, so I just deal with it like all the other spam I get elsewhere, but is it just coincidence that it started arriving the day after I opened the account? The only connection between the account and the spam is a tenuous one; the email address came free with the broadband connection that I most often use to go online with the stockbroker. I can’t think of any way the spammers could have harvested an email address I never actually use, just because it’s associated with an internet connection I do use, but am I overlooking something?

#2

I had a internet service provider that got hacked and didn’t have good security. Hackers got into an internal list they made up with our email accounts and our access passwords. They also used the providers servers on multiple weekends to spam us all weekend until someone went in on monday.

Your spam seems a bit more like their sign up form had a box hidden at the page bottom, that had to be unchecked, to not receive email solisitations. In the U.S. they have to include a unsubscribe contact for all email solicitors, and it has done a lot of good.

#3

…Except that at no point did I divulge this particular email address to the service I signed up for; it just happens to be the address associated with the connection by which I browse information relevant to the spam.

Three possibilities seem to present themselves:

-My ISP has sold my email address and browsing statistics to a spammer
-Someone has hacked my ISP and taken the above details
-Pure coincidence

#4

I’ve had a similar experience. See post #2 in this thread.

#5

I found that within one minute activating an email account I was receiving scam spam and sex ads. Someone else had the account name at one time.

#6

Try a reverse look up for your DNS and see what information is present for the regestered owner. Does something in the information give people a good guess at your email name. I hope you understand what I’m trying to convey here. I’m not sure I’m doing a good job with my explaination. Hopefully your email is not something like administrator@mydomain.com. I used to do reverse DNS look up to find owners for problem causing domains used by hackers or spamers.