Our company is hoping to make the credit card policy less burdensome without sacrificing sound business practices and controls. An idea was brought up to establish materiality thresholds for charges requiring approval by the cardholder's supervisor (such as anything less than $75 does not require approval). Do other companies adopt this approach?

I have not seen such exception in case of corporate credit cards, as usually T&E and corporate cards are perceived as High or Medium risk and is under high level of controls by AI (i.e. AppZen), internal audit or compliance teams.

If peer company wants to reduce bureaucracy and has sufficient comfort and maturing of T&E process, may be ok to have just supervisor notification as preventive control if such small spending will happen instead of asking for supervisor’s approval.

Similar solution I saw for small value POs which shall grant sufficient comfort level without additional approval.

There is a lot of variance with these types of thresholds and categories - every company has to decide what is the hot areas to keep tight controls and which can be loosened up.  The type of employee category and the frequency of transactions will really set the tone for your approach, in my opinion (i.e. - sales and marketing or claims adjusters with lots of dinners/lunches and travel vs. call center employees with infrequent company expenses).

I would expect there to be 'fraud' whether inadvertent or intentional below any threshold you set - just be sure to set up some sampling to keep an eye on the below threshold amounts (possibly using AI or analytics to identify anomalies). 

The latest materiality threshold I've experienced has been self-travel business meals under $25 don't require a receipt. However, this is for a company paid credit card and not a reimbursement to the employee, so the risk is lower in this situation.

There's nothing wrong with that level of $75 if, relative to your organization, that amount represents an appropriate materiality and frequency to alleviate some of the expense approval burden.  Again, just set some auditing guidelines to circle back on those transactions to gain some comfortability with the level of control and re-evaluate.

Good luck.