How do I use a second job offer to improve the lowball offer for the job that I prefer?

Here is my scenario: * Company A has offered me a salary of $150K (a market level salary). * Company B has offered me a salary of $100K (33% below market). * The jobs are otherwise similar. * If the salaries were comparable, I prefer to work at Company B. Strategy 1: I could tell Company B that I have an offer for $150K, and see if they can raise their offer to match. Strategy 2: I could tell Company B that I will only accept a market salary, and see if they raise their offer. Assuming they do, I would wait a couple days, then tell them I have an offer for $150K, and see if they can raise it again. With Strategy 1, my thinking is that they might be willing to raise the offer only once, but would be unwilling to raise it a second time for fear of being seen as "weak." So, I would use all my ammunition at once and see how high they can go with a revised offer. With Strategy 2, my thinking is that $50K is such a substantial gap that there's no way their revised offer would go as high as $150K. So, I would use the "below market" argument to ask them to raise the offer, then use the competing offer to ask them to raise it again. Which strategy (or another strategy) would result in the best offer from Company B?