front-running
noun[U]
STOCK MARKETukusthe usuallyillegalactof adealerbuyingsharesin acompanyafter they have had anorderfrom acustomertobuyalargenumberof the sameshares, which islikelyto have theresultthat theshareswill go up inprice. Thedealercan then make aprofitbysellingthesharesthat they havebought:
Front-running is when abrokerplacestradesfor his ownaccountbeforefulfillingorderspreviouslysubmittedby hiscustomer.