(a) In General.—Except as provided in subsection (c), a debtor is insolvent if the sum of the debtor's debts is greater than all of the debtor's assets at a fair valuation.

(b) Presumption.—A debtor who is generally not paying debts as they become due is presumed to be insolvent.

(c) Calculation.—A partnership is insolvent under subsection (a) if the sum of the partnership's debts is greater than the aggregate, at a fair valuation, of—

(1) all of the partnership's assets; and

(2) the sum of the excess of the value of each general partner's non-partnership assets over the partner's non-partnership debts.

(d) Assets.—For purposes of this section, assets do not include property that is transferred, concealed, or removed with intent to hinder, delay, or defraud creditors or that has been transferred in a manner making the transfer voidable under this subchapter.

(e) Debts.—For purposes of this section, debts do not include an obligation to the extent such obligation is secured by a valid lien on property of the debtor not included as an asset.