I work for a bank and I'm applying for a tourist Schengen visa via the Austrian embassy. I have gotten a NOC from my employer, which has the bank logo on top and states since when am I employed there, my designation and that my leave has been approved for the dates I intend to travel. It's also signed by HR. However, they're saying they don't have any stamp to use on that letter. I was wondering if this could be an issue or will the letter I have be alright?
For a visa application, a reference letter from the employer or No Objection Certificate help demonstrate ties to your home country and financial stability. There is no need, or requirement, that they have additional verification or stamping.
I made a Schengen Visa application in March 2018 and got it successfully. My employer only issued a NoC on their letterhead with logo, name and contact details and my HR signed it for me just like your case.
Thus I can confirm that if your letter is signed with the company's logo and details on it, it should be fine.
You can refer to this page for more info.