When it comes to selecting a font for a registered trademark symbol (®), there's no specific requirement or standard to follow. It's important to choose a font that matches the overall aesthetics and brand message of your company. The key is to ensure it's clearly visible and legible, without overshadowing your company's name or logo. Some popular choices are Arial, Times New Roman, and Helvetica, but it truly depends on the branding style you're aiming for. This symbol should always be used in conjunction with your trademark to represent your legal rights in the market.