Physician-investors who put morethan $25,000 into a mutual fund may begetting an unexpected check in the mail.What started as a small inquiry by theNational Association of Securities Dealers(NASD; 800-289-9999; www.nasd.org) late last year has now uncoveredwidespread failure to pass on volume discountsto large fund investors. The findingshave resulted in an order from theNASD that mutual fund sellers comb theirrecords and reimburse fund investors whoare eligible for the discounts and didn't getthem. Volume breakpoints generally startat $25,000, when the usual 5.75% salesload drops to 5%. At $100,000, the salescommission goes down to 3.5%. At thatlevel, a fund investor who didn't receivethe discount would receive a $2250refund, plus interest.