I personally don't think you would be out of line for asking them to cough up some "interest," however, I'll be amazed if you see that "extra" money. I mean, come on now...they've kept you waiting already. This means either they didn't have the repayment to begin with, on time, or you simply were not a priority in their financial goals. If they were up front and kept you "in the loop" and if their "problem" with adhering to the original time line was, in fact, true and honest and beyond their ability...then I feel like a TRUE FRIEND would OFFER to pay a bit more...but money is that creature that will make or break a friendship and also a family relationship.. Asking may be the straw that breaks this camel's back. Unless you had a WRITTEN, SIGNED contractual agreement, good luck enforcing ANYTHING...and I'd also wait until the entire original amount is in YOUR bank account before you bring this idea up...least they cop a major pissing attitude and refuse to pay you at all. I hate to be negative...but money does strange things to people and sometimes, what you think you can trust in a friendship...can turn to crap faster that a baby eating spinach for the first time....Good Luck!

Next time...give your money to ppl you can trust.