Shares of Puma Biotechnology Inc. largely maintained their value on Monday in their second day of trading on the New York Stock Exchange, falling just 3 percent during a volatile day for the broader markets.

The West L.A. cancer drug developer, which had moved from the Over-the-Counter Bulletin Board and sold 7.5 million new shares last week, announced on Monday that underwriters had exercised their option to purchase nearly 1.2 million additional shares, bringing the total raised in the offering to $138 million.

Puma’s offering has been considered among the most successful this year, with shares jumping more than 35 percent to close at $22.38 on Friday after the company priced an offering of 7.5 million new shares at $16.

The offering is expected to close on Wednesday.

Shares on Monday closed down 68 cents, or 3 percent, to $21.20.