Apple Music says they will stream music for free for their first 90 days, as a way of getting new listeners on board without asking them to open their wallets. But it's becoming clear that the deal likely won't be so sweet for one participant: independent record labels.

It was reported a couple weeks ago that Apple asked major labels, in negotiating streaming contracts, to use their music free of charge for the 90-day free period. Then, last week, one of Apple's proposed contracts with an unnamed indie label leaked, showing that the tech giant is asking indies to give up their music for free, too.

Now, A2IM, the largest indie label trade group, is advising its members -- who negotiate their deals with Apple individually -- to be wary of Apple's terms.

"Since a sizable percentage of Apple’s most voracious music consumers are likely to initiate their free trails at launch," the label group writes, "we are struggling to understand why rights holders would authorize their content on the service before October 1. This is especially true in light of the potential revenue damage to a music label’s iTunes download revenues and impact on their cash flow.

"Please do not feel rushed to sign Apple’s current offer," the letter continues.

A2IM's membership includes indie label heavyweights like Sub Pop, Matador, and Merge, as well as many smaller labels. "A2IM understands that each music label must determine for themselves their own promotional and commerce plans and that we respect our member labels’ independent entrepreneurial spirit. We simply suggest to our members that before agreeing to any direct licenses, that they should please consider all factors and their effects on their music label’s results."