I've definitely noticed the pricing for eggs at our neighborhood Trader Joes staying constant while the pricing at our neighborhood Safeway has doubled.

Trader Joes is like Costco and is known for driving hard bargains; they likely have a long-term contract. You overpay a bit but guarantee stability.

Still $3.50 at TJs in SF last week still, which is by far the cheapest around (that I'm aware of).

Pretty surprised they are still that low given prices elsewhere.

Loss leader, perhaps, to get people through the door and buy other stuff at a better markup. That and/or they've got long-term fixed price contracts.