To offer somewhat different advice, you could simply try and value his earlier efforts, not based on how much he's lost on his earlier company, but on how much the knowledge is worth to you.<p>For example, if you two started out as 50-50 partners and wanted to buy this knowledge from someone else, how much would you pay for it? Divide that cost by two, and that's how much you should "pay" your cofounder, whether in equity or cash.<p>The common wisdom is 50-50 no matter what, and it's a good rule of thumb; you don't want to feel like you have more or less at stake than he does and vice versa. If you're going to compensate him for his previous work, issue debt from your new company or pay upfront; I'd avoid changing the 50-50 split as much as possible.<p>And, of course, as other posters have mentioned, it could be that your current negotiating position indicates something negative about your cofounder, which is possible, but I don't think that's necessarily true.