What the signature appears to be
The signature looks like a monogram, not a full name. It appears to consist of:
Possibly two or three letters, overlapping
Dark paint, applied quickly
Placed discreetly in the lower corner, typical of modernist works
The letters could be interpreted (loosely) as something like:
“J B”
“I B”
Or a stylized initial followed by a surname initial
However, the execution is intentionally loose, which makes exact letter identification uncertain.
What this tells us
This is consistent with mid-20th-century European modern painters
Many artists of that era:
Used monograms
Avoided clear, commercial signatures
Signed quickly after finishing the composition
Importantly, the monogram does not correspond clearly to any widely documented major artist. That strongly suggests:
A regional or lesser-known professional artist
Possibly someone who exhibited locally or sold through small galleries