Not true. You can still raise on uncapped SAFEs. This will not trigger the YC MFN safe
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If the Company issues any Subsequent Convertible Securities with terms more favorable than those of this Safe (including, without limitation, a valuation cap and/or discount) prior to termination of this Safe, the Company will promptly provide YCombinator with written notice thereof, together with a copy of such Subsequent Convertible Securities and, upon written request of YCombinator, any additional information related to such Subsequent Convertible Securities as may be reasonably requested by the Investor.
In the event YCombinator determines that the terms of the Subsequent Convertible Securities are preferable to the terms of this instrument, YCombinator will notify the Company in writing within 10 days.
Promptly after receipt of such written notice from the Investor, the Company agrees to amend and restate this instrument to be identical to the instrument(s) evidencing the Subsequent Convertible Securities.
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So, any type of issue triggers the MFN and the jackpot to YC.
I don't want to be in a situation where they never raise again and then exit for $100M five years later and I only get my small little piece with no benefit for being in early.
What does this mean in practice?
To do that, you need more money, so you ask your friend YCombinator to help you.
In return, you promise to give them a special kind of toy money that you created (like monopoly money) that they can trade for real toys later when your store becomes bigger and better.
But for now, there are no real toys to exchange yet because the shop is still small and not opened yet.
Now, if you ask other friends for help and give them even better toy money (with better chances to get more toys), you need to tell YCombinator about it.
If YCombinator thinks the new toy money is better, they can ask you to change the toy money you gave them earlier to match the better one.
You have to do this quickly after YCombinator tells you they want the better toy money.