If Blue Shield were sold today, what's the highest price a buyer would pay? That's important to know because it represents the value of the community assets held by Blue Shield. It is also the amount of money at stake in the DMHC's recent ruling exempting Blue Shield from Article 11 of the Knox-Keene Act, which requires that the proceeds from the sale of a nonprofit be turned over to the public. It's impossible to say for certain how much that is, but a reasonable estimate is that the public would lose out on at least $10 billion if that ruling is not reversed or overturned.

This $10 billion estimate of Blue Shield's market value is based on the price Blue Shield recently paid to acquire Care1st Health Plan. Blue Shield paid $1.2 billion for the insurer, which has 500,000 customers enrolled mostly in Medicaid coverage. Blue Shield’s business prior to the acquisition consisted of 3.5 million members enrolled primarily in private-sector coverage, which is generally more profitable. So if Care1st is worth $1.2 billion, Blue Shield’s business, with seven times as many members, should be worth at least $8.4 billion. Add in Blue Shield’s $4.2 billion in reserves prior to the acquisition and the total comes to $12.6 billion. But to be conservative, let’s assume that Blue Shield’s total market value amounts to just $10 billion. 

Update: In its lawsuit against me, Blue Shield makes the following claim, which, while false, adds weight to the $10 billion estimate: 

The evidence shows that Mr. Johnson disclosed an attorney-client privileged estimate of the company’s value that he learned from the General Counsel.
a. Mr. Johnson made this disclosure (1) to the public via his blog and (2) to Chad Terhune of the L.A. Times.
(i) Ex. C-1 (Blog): On March 18, 2015, Mr. Johnson posted a blog entry titled “Why I resigned from Blue Shield and started this campaign.” He wrote: “But these benefits are paltry return (less than 1%) on a public asset, which is what Blue Shield is, that is worth perhaps as much as $10 billion.”

(ii) Ex. C-2 (Article): On March 18, 2015, Terhune wrote an article in the L.A. Times, which stated “Michael Johnson, who resigned as public policy director last week after 12 years at the company” “estimates the company could be worth as much as $10 billion.”

b. As explained in the Declaration of Seth Jacobs, the estimate Mr. Johnson disclosed was General Counsel’s estimate. The General Counsel shared this estimate with Mr. Johnson in the course of attorney-client privileged discussions. (Jacobs Decl. ¶ 16.) 

Here's the legal filing, with the claim highlighted.