My 1099 shows proceeds from a stock transaction (Cash + Stock) Gains are reported for the stock. Cash has proceeds but zero Cost & Gain. How should cash be handled?

Richie Brothers (RBA) acquired Insurance Auto Auction (IAA).  Here are some details that hopefully will help:

At the effective time of the First Merger, each outstanding share of IAA common stock, par
value $0.01 per share was converted into the right to receive $12.80 in cash and 0.5252 of a
share of RBA common stock, without par value, provided that IAA stockholders will receive
cash in lieu or any fractional RBA common stock to which they would otherwise be entitled.

U.S. holders of IAA common stock that exchange their shares of IAA common stock for
a combination of RBA common stock and cash in the Mergers will generally recognize
gain (but would not be permitted to recognize loss) in an amount equal to the lesser of:
(a) the amount of cash (excluding cash received in lieu of fractional RBA common
shares, if any) received by such U.S. holder in the Mergers; and (b) the excess, if any, of
(i) the sum of the amount of cash (excluding cash received in lieu of fractional RBA
common shares, if any) plus the fair market value of the RBA common shares (including
any fractional RBA common share deemed received) received by such U.S. holder in
exchange for its shares of IAA common stock in the Mergers, over (ii) such U.S. holder’s
tax basis in its shares of IAA common stock exchanged.
• The aggregate tax basis of the RBA common shares a U.S. holder receives in the Mergers
(including any fractional RBA common share deemed received) will generally be the
same as such U.S. holder’s aggregate tax basis in its shares of IAA common stock
surrendered in exchange therefor, decreased by the amount of cash (excluding cash
received in lieu of fractional shares, if any) such U.S. holder receives and increased by
the amount of gain (excluding any gain recognized with respect to cash received in lieu
of a fractional share), if any, such U.S. holder recognizes in the Mergers.
• U.S. holders of the common shares of IAA who receive cash in lieu of a fractional share
of RBA common stock generally will be treated as having received such fractional share
and then has having received cash in exchange for such fractional share. Gain or loss
generally will be recognized based on the difference between the amount of cash received
in lieu of the fractional share of common stock of RBA and the portion of the U.S.
holder’s aggregate tax basis in the IAA common stock surrendered allocable to the
fractional share.
• The tax consequences of the Mergers to a U.S. holder who is a “five-percent transferee
shareholder” (within the meaning of U.S. Treasury Regulations Section 1.367(a)-
3(c)(5)(ii)) of RBA will be as described above only if the U.S. holder files with the
Internal Revenue Service a gain recognition agreement in the form provided in U.S.
Treasury Regulations § 1.367(a)-8. Other considerations not described here may also
apply to such a holder. Any such U.S. holders should consult their own tax advisors with
respect to the decision to file a gain recognition agreement and the particular U.S. federal
income tax consequences of the Mergers to them.