```python
from fastapi import FastAPI
from fastapi.responses import JSONResponse
import asyncio
import helpers

app = FastAPI()


@app.get("/portfolio")
async def portfolio(symbols: str):
    symbol_list = [s.strip() for s in symbols.split(",") if s.strip()]
    tasks = [helpers.afetch_price(symbol) for symbol in symbol_list]
    prices_list = await asyncio.gather(*tasks)
    prices = dict(zip(symbol_list, prices_list))
    return JSONResponse(content={"prices": prices}, status_code=200)
```