Companies offering the drug risk reputation and legal repercussions, according to an Aug. 2 letter sent to CEOs at the two retail giants, as well as Kroger, Albertsons and medical distribution company McKesson Corp. The group said 6,000 Costco customers have signed a petition saying they will cancel their membership if the retailer starts selling the pills.

The religious coalition behind the petition owns about $172 million in shares of the five companies. The coalition was led by Boise, Idaho-based Inspire Investing, which manages $3 billion of assets, and includes the investment arm of the Southern Baptist churches and the American Family Association, a Christian fundamentalist group.