B. Riley Capital Management in Los Angeles proposed Wednesday to purchase all of United Online Inc.’s outstanding shares for $12.50 a share, or a total of $185 million. The price represents a 21 percent premium over the closing on Friday. The company first announced the B. Riley offer, without citing a price, on Monday. Headquartered in Woodland Hills, United Online owns Internet service providers NetZero and Juno but the company’s focus is on its customer loyalty programs and mobile commerce applications, such as MyPoints and List+. Earlier this year, United sold its social media site Classmates.com for $30 million and plans on doing the same with Classmate’s European counterpart StayFriends. Former chief executive Francis Lobo announced his resignation Nov. 3. “Our proposal provides United Online shareholders immediate liquidity at a time of tremendous uncertainty, including the recent departure of the company’s CEO,” Bryant Riley, chief executive of B. Riley Capital Management, said in a statement. “Given our longstanding history with and deep knowledge of United’s business, we are in a position to quickly effect the transaction.” As of Tuesday, B. Riley and its affiliates owned about 7.9 percent of United’s outstanding shares. United Online shares closed down 4 cents or a fraction of a percent to $11.63 on the Nasdaq.