Fair Isaac


said it will acquire

HNC Software


in a stock deal valued at about $810 million.

HNC shareholders will get 0.346 shares of new Fair Isaac stock for each HNC share, valuing HNC stock at about $22.18 based on Fair Isaac's Friday's close, a 27% premium to HNC's $17.44 closing price.

Fair Isaac, developer of a credit-scoring formula known as FICO, and it plans to use HNC's software to help it detect credit card fraud. The combined company will operate under the name Fair Isaac, and it expects the deal to boost earnings by about 10% immediately and offer cost savings of up to $35 million.

Shares of HNCS were trading up about 13.4% to $19.70 on the news, while Fair Isaac was recently down about 9%.