5000 more shares
A stockbroker was cold calling about a penny stock and found a taker.
"I think this one will really move said the broker, it's only $1 a share."
"Buy me 1000 shares." said the client. The next day the stock was at $2.
The client called the broker and said, "You were right, give me 5000 more shares." The next day the client looked in the paper and the stock was at $4. The client ran to the phone and called the broker, "Get me 10,000 more shares said the client." "Great!" said the broker.
The next day the client looked in the paper and the stock was at $9. Seeing what a great profit he had in just a few days, the client ran to the phone and told the broker, "Sell all my shares!" The broker said, "To whom? You were the only one buying that stock."