Updated with comments of Park Sterling CFO.CHARLOTE, N.C. ( TheStreet) -- Shares of Park Sterling Bank ( PSTB) declined 22% in morning trading Friday to $6.26, following the bank's announcement that it had priced a large offering of 23.1 million common shares at $6.50 per share. Trading on the offering also commenced on the Nasdaq. If successful, the stock sale will raise about $150 million in new capital. That is a very large sum considering the bank had $488 million in total assets, was already strongly-capitalized, profitable and had relatively light loan losses through the second quarter. Park Sterling has previously announced plans to expand into a regional player with between $8 and $10 billion in total assets through "continued organic growth and potential acquisitions in the Mid-Atlantic and Southeastern United States," according to a March filing with the Securities and Exchange Commission. The bank had previously said on July 29 that it expected "the offering price to be between $9 and $11 per share," according to SNL Financial. On Thursday, shares closed at $8, the same price as on July 29. The offering has been underwritten with Keefe, Bruyette & Woods serving as lead manager and the bank has granted the underwriters a 30-day option to purchase an additional 3.465 million shares. Park Sterling Bank also said the offering would close on August 18. Trading volume was very high on Friday, with 2.1 million shares changing hands by 11 a.m. While investors were apparently surprised by the $6.50 share price, it's too early to predict how successful the offering will be. CFO Steve Arnall told TheStreet that Sterling Park Bank's management expects today's offering to be the first in a series, as the bank still plans to raise about $400 million. "We'll get there, in several iteratations," he said. -- Written by Philip van Doorn in Jupiter, Fla.