It’s funny to think of IR departments deciding on one of the most strategic capital allocation issues at any company (or maybe you consider that the CFO is part of the investor relations team, that wouldn’t be completely wrong but it’s not the usual definition).
Yes, IR doesn't make the actual decision. That was said to me by a IR I knew in a previous company. Granted the decision making was obviously above his head and included other strategic decisions and the intents of the key stockholders, to say IR makes this decision is an exageration, but he produced the data to support and justify that decision. How much is that number flexible I guess depends on market regulation.