Workplaces like banks are very sensitive about what you can or can't do. This article is thin on details. Better source:

https://www.bloomberg.com/news/articles/2018-01-22/nordea-ba...

“It is widespread practice across the banking industry to restrict the personal account dealing of staff to prevent them taking positions in speculative investments, or which might expose them to a risk of financial loss and therefore impact their financial standing,” Kellberg said. “Nordea therefore, like all banks, has the right to set out policies in this area that apply to its staff.”