Another reason asking for more is safe
Companies spend thousands of dollars on recruiting costs on each role. That means if you walk away, they stand to lose a significant amount of money and have to restart the process again. Rationally, they should be willing to increase the offer by the same amount they’d lose by having you walk away.
How compensation works
At larger companies, they’ll have a compensation team that will create compensation bands for each role in the company. They buy data from large research groups in order to benchmark. So they’ll say, for a Level 5 Software Engineer, the base salary range is $150-160K, the equity range is 3000-5000 shares. Then the recruiter will determine where in the range you fall based on your experience and background. They will usually undershoot to give themselves room to wiggle in an upcoming negotiations.
This is a great strategy for finding out more information about comparable compensation. Fun fact, this is also a strategy recruiters at companies do to find out how much they should pay when giving out offers. Be sensitive when asking, but try:
"Hi [name], I was wondering if we could collaborate and share compensation information. We could all use a bit more transparency when it comes to pay and I’d love to share my offer and compare notes with you about it."