I already own shares, why do I need to meet minimum marketable parcel rules?

Your first purchase in a stock needs to be a minimum order value of $500 excluding fees

If your current shareholdings falls below $500 in market value, the additional order needs to bring the total market value up to at least $500.

eg. You purchased a holding in XYZ for a market value of $600, the value of your shares has fallen to $200. If you would like to purchase more XYZ you must purchase a minimum amount of $300 to meet minimum market rules.

ETF's and warrants are not subject tot he minimum marketable parcel (MMP) rule with Webull.