```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 = symbols.split(",")
    prices = await asyncio.gather(
        *[helpers.afetch_price(symbol) for symbol in symbol_list]
    )
    result = {
        "prices": {symbol: price for symbol, price in zip(symbol_list, prices)}
    }
    return JSONResponse(content=result)
```