At least two additional members besides Reps. Ritchie Torres (D-N.Y.) and Lois Frankel (D-Fla.) have left the Congressional Progressive Caucus in recent months, Axios has learned.

Why it matters: The caucus' membership has swelled in the last few election cycles to encompass nearly half the Democratic Caucus — a key marker of strength for Democrats' left flank.

What they're saying: Reps. Ruben Gallego (D-Ariz.) and Zoe Lofgren (D-Calif.) both confirmed to Axios that they allowed their membership in the caucus to lapse.

• Gallego, who is running for a hotly contested Senate seat in Arizona, said he left because "the prices went up" on the dues lawmakers must pay for membership. His departure was first reported by Politico.
• Lofgren similarly cited the "increase in expenses" and said she opted to allocate the money for a new district office following redistricting.

Context: Caucus membership dues come out of what is known as the members' representational allowance, or MRA, a lump sum that congressional offices also use to pay for staff and supplies.

Between the lines: The two lawmakers' reasoning differs from that of Frankel and Torres, both outspoken supporters of Israel who left due to the caucus' more pro-Palestinian lean.

Go deeper: Progressive Caucus loses another pro-Israel member