It may well be advantageous to you to make your gift to MSRI in appreciated stock instead of cash. By gifting the stock to MSRI (instead of selling it, and contributing the cash) you do not pay capital gains tax on its appreciation.
If you exceed your annual giving limit (typically up to 30% of your annual adjusted gross income when using fair market valuation or 50% if using cost basis) - you may carry forward and deduct the excess contribution for up to five years until it has been fully deducted.
It's easy to make a stock gift to MSRI. You can instruct your broker to transfer the shares directly. Just download, print and complete the attached form for stock transfers.
MSRI Development and Alumni Relations web pages are not intended as tax advice.
Know that individual financial circumstances require specific professional guidance. Please contact your legal and financial advisors to see how these general issues apply to you.