NEW YORK — R.H. Macy & Co. said Monday improvements in merchandising gross margins and continued expense reductions helped boost December cash flow by 30 percent.

Macy’s said earnings before interest, taxes, depreciation and amortization (EBITDA) rose to $266.1 million from $205 million in the same month of 1992, as reported.

Myron E. Ullman, chairman and chief executive officer, told employees on Friday, via a closed-circuit telecast in which he was bringing them up to date on developments connected with the bid from Federated Department Stores, that almost half, or $29 million, of the $61.1 million EBITDA gain came from East Coast operations. The West, which includes Bullock’s and Macy’s, contributed $23 million. The rest came from Macy’s specialty store operations and I. Magnin.

Total sales slipped to $1.17 billion from $1.19 billion. On a comparable-store basis and adjusted for the discontinuation of the electronics business, sales increased 1.7 percent. This confirms a report in a story in these columns on Jan. 7.

The company said it had $279 million in cash as of Dec. 31, which was $40 million ahead of plan. Macy’s also had $475 million of bank lines available.