I read this sentence in “The Sydney Morning Herald”: "Bingham-Hall symbolises the new breed of women cashing in their senior executive positions for seats on the boards of Australia’s biggest companies." Isn't the phrase supposed to be "cashi in on", or is this a special usage peculiar to Australia?
If you cash in something, you exchange it for something else, usually cash.
I had no reserves when I lost my job, so I cashed in my life assurance policies.
If you cash in on something, you take advantage of it. Disapproval is often implied.
The record company is re-releasing Fred Toneless's old albums, cashing in on the public interest in his drug problems.