Stimulates the transcription of various genes by recognizing and binding to a CCAAT motif in promoters (By similarity). Interacts with REF6 to directly regulate SOC1 transcription in response to flowering signals from photoperiod and gibberellic acid pathways (PubMed:25105952). Heterotrimeric transcription factor composed of three components, NF-YA, NF-YB and NF-YC. Interacts with NFYA2, NFYB2, CO and RGA. Interacts with REF6 (via N-terminus). Ubiquitous. Present in etiolated seedlings. Belongs to the NFYC/HAP5 subunit family. Truncated N-terminus.