TOT: eBay

It's because HMRC require them to report sales over a certain threshold, to prevent people making trading income without declaring it for tax:

Theo

Thanks for that explanation. My sales are minimal. In fact, I got an email from eBay asking me to check my details for security as I have not logged on for a year, when I noticed this information. Is eBay sufficiently reputable that I should just tell them? I would say an NI number is less sensitive than bank details. l

The danger is that an acquired NI number could be used to gain fraudulent access to or open accounts etc.

It’s a number that perhaps should be well guarded. When hiring cars, for example, the hire firm checks your licence details online via the NI number, but I always get the security code first and give them that instead.

Thanks, I won't disclose my NI number then unless or until they insist, quoting authority.

From:

To prevent identity fraud, do not share your National Insurance number with anyone who does not need it.

These organisations may need to know what your number is:

... websites or apps you sell goods or services through, if they’re required to report to HMRC ...

So eBay may be required to obtain your NI number.

John

Thanks, I'll supply it if there is a good reason but not pre-emptively.

A solution for those with low numbers of sales (and the OP said he hadn’t logged on to his eBay account in year) might be to sell via another medium.

Your quote says that the NI number is ‘required’ *if required to report to HMRC*. If the OP is not required so to do, eBay does not need to know his NI…

I have been selling bits and pieces on eBay for more than 20 years and never been asked for a NI number

eBay have my name, address, phone number and bank account details, so I cant imagine thats not enough for HMRC to identify me

The rules didn't actually change in 2024, but HMRC just got a bit hotter on them ...

Rachelreeves needs the help of the poor, Be ready to pay in the morning.

(With apologies)

"Depending on your yearly sales or number of sales transactions, you MAY need to provide eBay with your National Insurance (NI) number"

The OP posted this:

My interpretation was that personal details section was standard to all customers and not customised for me. Maybe someone else could look.

I did, no sign of an NI number field.

My experience is that when sales pass £1,740 or 30 sales, around last October in my case IIRC, eBay will ask for the NI number and say why they want it.

Don't forget, eBay income is not the same as profit. Expenses (postage, packaging materials, purchasing stock costs (if relevant), etc) have to deducted to establish the taxable profit.

I am surprised. In my case it's in Account Settings > Personal Info at the bottom, below date of birth.

In message snipped-for-privacy@4ax.com, at 18:11:53 on Fri, 10 Apr 2026, Peter Johnson snipped-for-privacy@parksidewood.nospam remarked:

The reporting threshold is sales, not profit.

Calculating the profit isn't always easy, because apportioning a buy-price to each item in a job-lot is difficult.

Later today I'll be bidding on a job lot that contains various vintage enamelled tins, a 1960's "AA" badge and a few other items which are probably just scrap. If I sell the badge on eBay, how does one assign a buy-price to it? Or if I put the badge on my car, and sell the tins, how to account for that?