São contas de resultado que se anulam quando da emissão dos demonstrativos (balancing accounts), por isto são provisórias.

http://www.ipu.msu.edu/library/pdfs/NARUC Ratecase Audit Man...

Suspense and Clearing Accounts
Suspense or clearing accounts are auxiliary accounts that exist for technical reasons and which
are repeatedly cleared. Postings may be made to a clearing account due to a time gap between
accounting transactions, organizational task distribution, or accounting transactions requiring
clarification. The auditor should examine the utility’s reasons for using clearing accounts and its
method for clearing them. The auditor should verify that these accounts are routinely cleared
and that the method used for clearing is appropriate. If not cleared in the appropriate time
period, costs may not be adequately reflected in rates for these expenditures. Be sure the account
is not routinely over or under amortized.

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Note added at 3 hrs (2014-02-19 23:01:13 GMT)
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Às ordens, amigo!