Just days after announcing plans to raise $10 million in a preferred stock offering, BofI Holding Inc. in San Diego now says it intends to raise $18 million.

The $2 billion-asset parent of the Bank of Internet USA announced Tuesday that it is amending the stock offering and will now sell 18,000 shares at $1,000 each, rather than the 10,000 shares it initially planned to sell.

Gregory Garrabrants, the bank's president and chief executive, said in a brief interview that legal reasons prohibit him from disclosing the reason for the increase, but Andrew Liesch, an analyst with Sandler O’Neill & Partners L.P., said he suspects it was due to higher demand from investors.  

Each preferred share will pay an annual dividend of 6% will be convertible into 61.92 shares of BofI common stock, which is unchanged from the initial deal announced Thursday.

The company has said that it intends to use the proceeds of the stock sale to support growth and beef up its capital base.

BofI's shares fell 3.2% Tuesday to close at $13.63.