New Client Outside Basis

[Drphibes]

So, a new client on extension has come to me with 17 partnerships, all as a limited partner, and not publicly traded.  The partnerships involve apartment complexes where some of the Partnerships own %'s of other Partnerships.  Some Partnerships are over 10 years running for him (he only has the last 7 years of returns, tossed all the priors).  Client has no outside basis calculations (his long term tax guy retired and had never brought the subject up to the client), has some rather large cash distributions for 2021, negative capital accounts on some K-1's and there are all 3 types of loan balances showing on each of the K-1s.  Question, is there an easy way to calculate the outside basis for each Partnership without going all the way back to the beginning of him buying into each Partnership and calculating the outside basis for each year until brought to present to determine if any of the cash distributions are taxable?  He basically just bought into each Partnership (for rather large amounts of money) with no other cash infusions.  As always, thanks in advance!

[sjrcpa]

No easy way.