In the original post Patrick already touched on the Japan case, but one thing I'd add is that one of the pieces of paperwork you must hand to your new employer is your final tax slip from your previous employer showing how much tax you have paid in the current year. From there it's trivial to calculate your previous salary.
There are ways around it but it seems most people go with "my base was XX.... and that's one of the reasons I'm out there looking to change jobs."
"...one of the pieces of paperwork you must hand to your new employer is your final tax slip from your previous employer showing how much tax you have paid in the current year..."
Are you referring to Japan?
I've worked in two states in the USA and never been required to produce such documentation.
I've always had to do that in the UK. Your previous employer gives you a form called a P45 when you leave that has information about your tax code and your earnings for the previous year.
The new employer just needs your details to identify you correctly with HMRC.
You can give them sufficient detail without handing over your P45 or income data. I have never given a P45 to a new employer and it has never been a problem.
It's possible that your tax code will reveal some information, if you're still in the same financial year, but this is an unreliable way of calculating salary.
Correct. A difference for the UK is that salary bands are often (not always) disclosed in an advertisement or told to a head hunter in advance. Not always, but enough that not doing so raises eyebrows and concerns about corporate ethics for me (and my friends).
The obvious caveat in this is that they could only estimate an average salary. You could state that your salary progresed rapidly during your previous employment, although they may not buy it.
> your final tax slip from your previous employer showing how much tax you have paid in the current year.
Do you mean in Japan or the US? Because you certainly don't have to do that in the US.
> From there it's trivial to calculate your previous salary.
And even if you did do it in the US it would be impossible to calculate your salary from it because it depends on how many exemptions you claimed in your W4 (which you can change at any time - it doesn't have to be how many children you have, it's basically a number to fine tune how much tax you pay so you don't overpay and need a refund).
There are ways around it but it seems most people go with "my base was XX.... and that's one of the reasons I'm out there looking to change jobs."