Large percent changes on stockholders equity section of 10K

Without having looked at the 10K, my guess is that some authorized restricted stock was cashed in (or awarded and offset by new common - I haven't looked up the details), thereby reducing the liability on the balance sheets. The other item you noticed probably is offset by reduction of assets, and is an accounting timing thing, matching to periods and matching to actual dispositions. Or, if BMY had posted losses, then its current accumulating earnings (retained) are reducing the accumulated losses .

I believe drug companies are best analyzed by looking at the current patent life of their products, the effects of expiration, and their drug pipelines (new, pending tests and approvals).